JP6808249B2 - Force sensor - Google Patents

Description

The present invention relates to a force sensor, and more particularly to a sensor having a function of outputting a force acting in a predetermined axial direction and a moment (torque) acting around a predetermined rotation axis as an electric signal.

For example, Patent Document 1 describes a force sensor having a function of outputting a force acting along a predetermined axial direction and a moment acting around a predetermined rotation axis as an electric signal, and the force of an industrial robot. Widely used for control. In recent years, it has also been adopted for life support robots. As the market for force sensors has expanded, there has been a growing demand for lower prices and higher performance of force sensors.

By the way, as a force sensor, a capacitance type force sensor that detects a force or a moment based on a fluctuation amount of a capacitance value of a capacitance element, or a force based on a fluctuation amount of an electric resistance value of a strain gauge. Alternatively, a strain gauge type force sensor that detects the moment is used. Of these, the strain gauge type force sensor has a complicated structure of the strain generating body (elastic body), and a step of attaching a strain gauge to the strain generating body is required in the manufacturing process thereof. As described above, it is difficult to reduce the price of the strain gauge type force sensor because the manufacturing cost is high.

On the other hand, the capacitance type force sensor can measure the force or moment acted by one set of parallel flat plates (capacitive elements), which simplifies the structure of the strain generating body including the capacitive element. be able to. That is, the capacitance type force sensor has an advantage that the price can be easily reduced because the manufacturing cost is relatively low. Therefore, if the structure of the strain-causing body including the capacitance element is further simplified, the price of the capacitance type force sensor can be further reduced.

Against this background, the applicant is arranged in the international patent application PCT / JP2017 / 008843 (Japanese Patent Application No. 2017-599470) so as to surround the origin O when viewed from the Z-axis direction, and is arranged by the action of a force or a moment. We have proposed a force sensor that has an annular deformed body that causes elastic deformation and the deformed body has a curved portion. More specifically, the plasmodium is positioned alternately with two fixed parts fixed to the XYZ three-dimensional coordinate system and two fixed parts in the annular path of the deformed body, and the force or moment. It has two receiving parts that are affected and four deformed parts that are positioned between the fixed part and the receiving part that are adjacent to each other in the annular path, and each deformed part has, for example, the Z axis. It is a force sensor that is curved (bulged) in the negative direction.

As a result of diligent studies to further improve the force sensor as described above, the applicant has provided a curved portion at the connecting portion between the deformed portion, the fixed portion and the receiving portion, thereby stressing the connecting portion. We have found that it is possible to alleviate concentration and further improve the reliability of the force sensor.

Japanese Unexamined Patent Publication No. 2004-354049 The present invention is based on the above findings. That is, an object of the present invention is to provide a capacitance type force sensor having a deformed body having a curved portion and also having high reliability.

The force sensor according to the first aspect of the present invention detects at least one of a force in each axial direction and a moment around each axis in the XYZ three-dimensional coordinate system.
A closed-loop deformed body that elastically deforms due to the action of force or moment,
A detection circuit that outputs an electric signal indicating an acting force or moment based on the elastic deformation generated in the deformed body is provided.
The deformed body is positioned adjacent to at least two fixed parts fixed to the XYZ three-dimensional coordinate system and the fixed parts in a closed loop path of the deformed body, and is affected by a force or a moment. It has at least two receiving portions and a deformed portion located between the fixed portion and the receiving portion that are adjacent to each other in the closed loop path.
The deformed part is
A main curved portion having a main curved surface curved in the Z-axis direction,
A fixed portion-side curved portion that connects the main curved portion and the corresponding fixed portion and has a fixed portion-side curved surface that is curved in the Z-axis direction.
The main curved portion and the corresponding receiving portion are connected to each other, and the receiving portion side curved portion having a curved surface on the receiving portion side curved in the Z-axis direction is provided.
The main curved surface, the curved surface on the fixed portion side, and the curved surface on the receiving portion side are both provided on the Z-axis positive side or the Z-axis negative side of the deformed portion, and the directions of curvature are different from each other. ,
The detection circuit outputs the electric signal based on the elastic deformation generated in the main curved portion.

In this force sensor, the main curved surface, the fixed portion side curved surface, and the force receiving portion side curved surface are both provided on the Z-axis negative side of the deformed portion.
The main curved surface is curved toward the negative side of the Z axis.
The curved surface on the fixed portion side and the curved surface on the receiving portion side may be curved toward the positive side of the Z axis.

Further, the force sensor according to the second aspect of the present invention detects at least one of the force in each axial direction and the moment around each axis in the XYZ three-dimensional coordinate system.
A closed-loop deformed body that elastically deforms due to the action of force or moment,
A detection circuit that outputs an electric signal indicating an acting force or moment based on the elastic deformation generated in the deformed body is provided.
The deformed body is positioned adjacent to at least two fixed parts fixed to the XYZ three-dimensional coordinate system and the fixed parts in a closed loop path of the deformed body, and is affected by a force or a moment. It has at least two receiving portions and a deformed portion located between the fixed portion and the receiving portion that are adjacent to each other in the closed loop path.
The deformed part is
A main curved portion having a main curved surface curved inward or outward of the closed loop path,
A fixed portion-side curved portion that connects the main curved portion and the corresponding fixed portion and has a fixed portion-side curved surface that is curved toward the inside or outside of the closed loop-shaped path.
A receiving portion-side curved portion that connects the main curved portion and the corresponding receiving portion and has a receiving portion-side curved surface that is curved toward the inside or outside of the closed loop-shaped path. Have and
The main curved surface, the curved surface on the fixed portion side, and the curved surface on the receiving portion side are both provided on the inner peripheral surface or the outer peripheral surface of the deformed body, and the directions of curvature are different from each other.
The detection circuit outputs the electric signal based on the elastic deformation generated in the main curved portion.

Each of the above force sensors is a fixed body fixed to the XYZ three-dimensional coordinate system and
A receiving body that moves relative to the fixed body by the action of a force or a moment is further provided.
The fixed body is connected to each fixed portion via a fixed body side connecting member.
The receiving body may be connected to each receiving portion via a receiving body side connecting member.

Each of the above force sensors is a fixed body fixed to the XYZ three-dimensional coordinate system and
A receiving body that moves relative to the fixed body by the action of a force or a moment is further provided.
The fixed body is integrally formed with each fixed portion, and is formed.
The receiving body may be integrally formed with each receiving portion.

The deformed body is arranged so as to surround the origin when viewed from the Z-axis direction.
Through holes through which the Z-axis is inserted may be formed in the fixed body and the receiving body, respectively.

The deformed body may have a circular or rectangular shape centered on the origin when viewed from the Z-axis direction.

The force sensor according to the third aspect of the present invention detects at least one of the force in each axial direction and the moment around each axis in the XYZ three-dimensional coordinate system.
A fixed body fixed to the XYZ three-dimensional coordinate system,
A closed-loop deformed body that surrounds the Z-axis, is connected to the fixed body, and causes elastic deformation by the action of a force or moment.
A receiving body that is connected to the deformed body and moves relative to the fixed body by the action of a force or moment.
A detection circuit that outputs an electric signal indicating a force or moment acting on the receiving body based on the elastic deformation generated in the deformed body is provided.
The deformed body has at least two fixed portions connected to the fixed body and at least two receiving portions connected to the receiving body and positioned adjacent to the fixed portion in the circumferential direction of the deformed body. And a deformed portion positioned between the adjacent fixed portion and the receiving portion.
The deformed part is
A main curved portion having a main curved surface curved in the Z-axis direction,
A fixed portion-side curved portion that connects the main curved portion and the corresponding fixed portion and has a fixed portion-side curved surface that is curved in the Z-axis direction.
The main curved portion and the corresponding receiving portion are connected to each other, and the receiving portion side curved portion having a curved surface on the receiving portion side curved in the Z-axis direction is provided.
The main curved surface, the curved surface on the fixed portion side, and the curved surface on the receiving portion side are both provided on the Z-axis positive side or the Z-axis negative side of the deformed portion, and the directions of curvature are different from each other. ,
The detection circuit outputs the electric signal based on the elastic deformation generated in the main bending portion.
The receiving body has a receiving body surface facing the Z-axis positive direction or the Z-axis negative direction.
The fixed body has a fixed body surface facing the Z-axis positive direction or the Z-axis negative direction.
The distance from the deformed body to the surface of the receiving body and the distance from the deformed body to the surface of the fixed body are different.

Further, the force sensor according to the fourth aspect of the present invention detects at least one of the force in each axial direction and the moment around each axis in the XYZ three-dimensional coordinate system.
A fixed body fixed to the XYZ three-dimensional coordinate system,
A closed-loop deformed body that surrounds the Z-axis, is connected to the fixed body, and causes elastic deformation by the action of a force or moment.
A receiving body that is connected to the deformed body and moves relative to the fixed body by the action of a force or moment.
A detection circuit that outputs an electric signal indicating a force or moment acting on the receiving body based on the elastic deformation generated in the deformed body is provided.
The deformed body has at least two fixed portions connected to the fixed body and at least two receiving portions connected to the receiving body and positioned adjacent to the fixed portion in the circumferential direction of the deformed body. And a deformed portion positioned between the adjacent fixed portion and the receiving portion.
The deformed part is
A main curved portion having a main curved surface curved inward or outward of the closed loop path,
A fixed portion-side curved portion that connects the main curved portion and the corresponding fixed portion and has a fixed portion-side curved surface that is curved toward the inside or outside of the closed loop-shaped path.
A receiving portion-side curved portion that connects the main curved portion and the corresponding receiving portion and has a receiving portion-side curved surface that is curved toward the inside or outside of the closed loop-shaped path. Have and
The main curved surface, the curved surface on the fixed portion side, and the curved surface on the receiving portion side are both provided on the inner peripheral surface or the outer peripheral surface of the deformed body, and the directions of curvature are different from each other.
The detection circuit outputs the electric signal based on the elastic deformation generated in the main bending portion.
The receiving body has a receiving body surface facing the Z-axis positive direction or the Z-axis negative direction.
The fixed body has a fixed body surface facing the Z-axis positive direction or the Z-axis negative direction.
The distance from the deformed body to the surface of the receiving body and the distance from the deformed body to the surface of the fixed body are different.

In the force sensor according to the third and fourth aspects described above, the surface of the receiving body and the surface of the fixed body are parallel to the XY plane.
The Z coordinate value of the surface of the receiving body and the Z coordinate value of the surface of the fixed body may be different.

The deformed body surrounds one of the fixed body and the receiving body,
The other of the fixed body and the receiving body may surround the deformed body.

The fixed body, the receiving body, and the deformed body may all have a circular or rectangular shape centered on the origin when viewed from the Z-axis direction.

The at least two fixing portions are formed integrally with the fixing body.
The at least two receiving portions may be formed integrally with the receiving body.

In each of the above force sensors, n (n is a natural number of 2 or more) of the at least two receiving portions and the at least two fixing portions are provided, and the deformed body is provided along the closed loop path. Positioned alternately,
2n (n is a natural number of 2 or more) are provided, and one of the deformed portions may be arranged between the adjacent receiving portion and the fixed portion.

Further, in each of the above force sense sensors, the detection circuit has a displacement sensor arranged in the main bending portion, and outputs an electric signal indicating the acting force or moment based on the measured value of the displacement sensor. You can do it.

The displacement sensor includes a capacitive element having a displacement electrode arranged on the main bending portion and a fixed electrode arranged facing the displacement electrode and connected to the at least two fixed portions.
The detection circuit may output an electric signal indicating an acting force or moment based on the amount of fluctuation in the capacitance value of the capacitance element.

Alternatively, the at least two receiving portions and the at least two fixing portions are each provided with two.
Each fixed portion is arranged symmetrically with respect to the Y axis at a portion where the deformed body overlaps the X axis when viewed from the Z axis direction.
Each receiving portion is arranged symmetrically with respect to the X axis at a portion where the deformed body overlaps the Y axis when viewed from the Z axis direction.
Four of the deformed portions are provided, and one is arranged between the adjacent receiving portion and the fixed portion. The displacement sensor is a four displacement electrode arranged in each main curved portion of each deformed portion. And four capacitive elements having four fixed electrodes arranged opposite to each displacement electrode and connected to each corresponding fixed portion.
The four capacitive elements are arranged one by one at four sites where the deformed body intersects the V-axis and the W-axis when viewed from the Z-axis direction.
The detection circuit may output an electric signal indicating an acting force or moment based on the amount of fluctuation in the capacitance value of the four capacitance elements.

A support on the side of the deformed body is connected to the main curved portion of the deformed body.
The displacement electrode may be supported by the corresponding deformed body side support.

The force sensor according to the fifth aspect of the present invention detects at least one of the force in each axial direction and the moment around each axis in the XYZ three-dimensional coordinate system.
A closed-loop deformed body that elastically deforms due to the action of force or moment,
A detection circuit that outputs an electric signal indicating an acting force or moment based on the elastic deformation generated in the deformed body is provided.
The deformed body is positioned adjacent to each fixed part in a closed loop-shaped path of the deformed body and four fixed parts fixed to the XYZ three-dimensional coordinate system, and is subjected to the action of a force or a moment. It has one receiving portion and a deformed portion positioned between each fixed portion and each receiving portion adjacent to each other in the closed loop path.
The deformed part is
A main curved portion having a main curved surface curved in the Z-axis direction,
A fixed portion-side curved portion that connects the main curved portion and the corresponding fixed portion and has a fixed portion-side curved surface that is curved in the Z-axis direction.
The main curved portion and the corresponding receiving portion are connected to each other, and the receiving portion side curved portion having a curved surface on the receiving portion side curved in the Z-axis direction is provided.
The main curved surface, the curved surface on the fixed portion side, and the curved surface on the receiving portion side are both provided on the Z-axis positive side or the Z-axis negative side of each deformed portion, and the directions of curvature are different from each other. ,
The detection circuit outputs the electric signal based on the elastic deformation generated in the main curved portion.

Further, the force sensor according to the sixth aspect of the present invention detects at least one of the force in each axial direction and the moment around each axis in the XYZ three-dimensional coordinate system.
A closed-loop deformed body that elastically deforms due to the action of force or moment,
A detection circuit that outputs an electric signal indicating an acting force or moment based on the elastic deformation generated in the deformed body is provided.
The deformed body is positioned adjacent to the four fixed parts fixed to the XYZ three-dimensional coordinate system and the fixed parts in a closed loop-shaped path of the deformed body, and is subjected to the action of a force or a moment. It has one receiving portion and a deformed portion positioned between the fixed portion and the receiving portion that are adjacent to each other in the closed loop path.
The deformed part is
A main curved portion having a main curved surface curved inward or outward of the closed loop path,
A fixed portion-side curved portion that connects the main curved portion and the corresponding fixed portion and has a fixed portion-side curved surface that is curved toward the inside or outside of the closed loop-shaped path.
A receiving portion-side curved portion that connects the main curved portion and the corresponding receiving portion and has a receiving portion-side curved surface that is curved toward the inside or outside of the closed loop-shaped path. Have and
The main curved surface, the curved surface on the fixed portion side, and the curved surface on the receiving portion side are both provided on the inner peripheral surface or the outer peripheral surface of the deformed body, and the directions of curvature are different from each other.
The detection circuit outputs the electric signal based on the elastic deformation generated in the main curved portion.

In the force sensor according to the fifth and sixth aspects described above, the four receiving portions and the four fixing portions are alternately positioned along the closed loop-shaped path of the deformed body.
Eight of the deformed portions may be provided, and one may be arranged between the adjacent receiving portion and the fixed portion.

The above force sensor is a fixed body fixed to the XYZ three-dimensional coordinate system and
A receiving body that moves relative to the fixed body by the action of a force or a moment is further provided.
The four fixing portions are connected to the fixed body via a fixed body side connecting member.
The four receiving portions may be connected to the receiving body via a receiving body side connecting member.

Alternatively, the above force sensor is a fixed body fixed to the XYZ three-dimensional coordinate system.
A receiving body that moves relative to the fixed body by the action of a force or a moment is further provided.
The four fixing portions are integrally formed with the fixed body.
The four receiving portions may be integrally formed with the receiving body.

The closed-loop variant may have a circular or rectangular shape.

The detection circuit has a displacement sensor arranged in the main bending portion, and may output an electric signal indicating an acting force or moment based on a measured value of the displacement sensor.

The displacement sensor includes a capacitive element having a displacement electrode arranged on the main curved portion and a fixed electrode arranged facing the displacement electrode and connected to at least one of the four fixed portions.
The detection circuit may output an electric signal indicating an acting force or moment based on the amount of fluctuation in the capacitance value of the capacitance element.

Two of the four receiving portions are arranged symmetrically with respect to the origin on the X axis when viewed from the Z axis direction.
The remaining two of the four receiving portions are arranged symmetrically with respect to the origin on the Y axis when viewed from the Z axis direction.
When the V-axis and W-axis that pass through the origin and form 45 ° with respect to the X-axis and Y-axis are defined on the XY plane,
Two of the four fixed portions are arranged symmetrically with respect to the origin on the V axis when viewed from the Z axis direction.
The remaining two of the four fixed portions are arranged symmetrically with respect to the origin on the W axis when viewed from the Z axis direction.
Eight of the deformed portions are provided, and one is arranged between the adjacent receiving portion and the fixed portion. The displacement sensor is eight displacement electrodes arranged in each main curved portion of each deformed portion. And eight capacitive elements having eight fixed electrodes arranged opposite to each displacement electrode and connected to each corresponding fixed portion.
The detection circuit may output an electric signal indicating an acting force or moment based on the amount of fluctuation in the capacitance value of the eight capacitance elements.

In each of the above force sensors, the main curved surface of the main curved portion may be formed of a smooth curved surface having no inflection point when observed along the closed loop path.

Alternatively, in each of the above force sensors, the main curved surface of the main curved portion may be formed of a curved surface along an arc when observed along the closed loop path.

Alternatively, in each of the above force sensors, the main curved surface of the main curved portion may be formed of a curved surface along an elliptical arc when observed along the closed loop path.

In each of the above force sensors, the main curved portion may have a non-curved straight section in at least one end region when observed along the closed loop path.

The force sensor according to the seventh aspect of the present invention detects at least one of the force in each axial direction and the moment around each axis in the XYZ three-dimensional coordinate system.
A fixed body that surrounds the Z axis and is fixed to the XYZ three-dimensional coordinate system,
A closed-loop deformed body that surrounds the Z-axis, is connected to the fixed body, and causes elastic deformation by the action of a force or moment.
A receiving body that surrounds the Z-axis, is connected to the deformed body, and moves relative to the fixed body by the action of a force or moment.
A detection circuit that outputs an electric signal indicating a force or moment acting on the receiving body based on the elastic deformation generated in the deformed body is provided.
The deformed body has at least two fixed portions connected to the fixed body and at least two receiving portions connected to the receiving body and positioned adjacent to the fixed portion in the circumferential direction of the deformed body. And a deformed portion positioned between the adjacent fixed portion and the receiving portion.
The deformed portion has a curved portion curved in a predetermined direction.
The detection circuit outputs the electric signal based on the elastic deformation generated in the curved portion.
The receiving body has a receiving body surface facing the Z-axis positive direction or the Z-axis negative direction.
The deformed body has a deformed body surface oriented in the same direction as the surface of the receiving body, and the Z coordinate of the surface of the deformed body is different from the Z coordinate of the surface of the receiving body.

The fixed body has a fixed body surface oriented in the same direction as the surface of the receiving body, and the Z coordinate of the surface of the fixed body is different from the Z coordinate of the surface of the deformed body and the Z coordinate of the surface of the receiving body. It's okay.

Alternatively, the force sensor according to the eighth aspect of the present invention detects at least one of the force in each axial direction and the moment around each axis in the XYZ three-dimensional coordinate system.
A fixed body that surrounds the Z axis and is fixed to the XYZ three-dimensional coordinate system,
A closed-loop deformed body that surrounds the Z-axis, is connected to the fixed body, and causes elastic deformation by the action of a force or moment.
A receiving body that surrounds the Z-axis, is connected to the deformed body, and moves relative to the fixed body by the action of a force or moment.
A detection circuit that outputs an electric signal indicating a force or moment acting on the receiving body based on the elastic deformation generated in the deformed body is provided.
The deformed body has at least two fixed portions connected to the fixed body and at least two receiving portions connected to the receiving body and positioned adjacent to the fixed portion in the circumferential direction of the deformed body. And a deformed portion positioned between the adjacent fixed portion and the receiving portion.
The deformed portion has a curved portion curved in a predetermined direction.
The detection circuit outputs the electric signal based on the elastic deformation generated in the curved portion.
The fixed body has a fixed body surface facing the Z-axis positive direction or the Z-axis negative direction.
The deformed body has a deformed body surface oriented in the same direction as the fixed body surface, and the Z coordinate of the deformed body surface is different from the Z coordinate of the fixed body surface.

In the force sensor according to the seventh and eighth aspects, the fixed body, the receiving body, and the deformed body all have a circular or rectangular shape centered on the origin when viewed from the Z-axis direction. It's okay.

Further, the receiving body and the fixed body may be arranged so as to sandwich the deformed body.

Alternatively, the receiving body and the fixed body may be arranged on the same side with respect to the deformed body.

Further, the fixed body or the force receiving body has a sensor-side convex portion in a region facing the mounting object to which the force sensor is mounted.
When the force sensor is attached to the attachment object, the sensor-side convex portion is housed in the attachment recess formed in the attachment object.
The sensor-side convex portion may be pressed toward the inside of the mounting recess by the inner peripheral surface of the mounting recess.

Alternatively, the fixed body or the receiving body has a sensor-side recess in a region facing the mounting object to which the force sensor is mounted.
The sensor-side concave portion accommodates a mounting convex portion formed on the mounting object when the force sensor is mounted on the mounting target.
The inner peripheral surface of the sensor-side recess may press the mounting convex portion toward the inside of the sensor-side recess.

The force sensor according to the ninth aspect of the present invention is attached to an object to be mounted having a mounting recess, and detects at least one of a force in each axial direction and a moment around each axis in the XYZ three-dimensional coordinate system. And
Plasmodium that elastically deforms due to the action of force or moment
A fixed body connected to the deformed body and fixed with respect to XYZ three-dimensional coordinates,
It is provided with a receiving body that is connected to the deformed body and moves relative to the fixed body by the action of a force or a moment.
The fixed body or the receiving body has a sensor-side convex portion housed in the mounting recess in a region facing the mounting object.
When the sensor-side convex portion is housed in the mounting recess, the inner peripheral surface of the mounting recess presses the convex portion toward the inside of the mounting recess.

The acute angle formed by the outer peripheral surface of the convex portion on the sensor side with respect to the mounting direction when the force sensor according to the ninth aspect is mounted on the mounting object is the inner peripheral surface of the mounting recess with respect to the mounting direction. It may be smaller than the acute angle of the eggplant.

The sensor-side convex portions may be provided so as to face each other at intervals when viewed from the mounting direction when the force sensor is mounted on the mounting object, or may be continuously provided along a closed loop-shaped path. It may be provided intentionally or intermittently.

The force sensor according to the tenth aspect of the present invention is attached to an object to be mounted having a mounting protrusion, and detects at least one of a force in each axial direction and a moment around each axis in the XYZ three-dimensional coordinate system. It's a thing
Plasmodium that elastically deforms due to the action of force or moment
A fixed body connected to the deformed body and fixed with respect to XYZ three-dimensional coordinates,
It is provided with a receiving body that is connected to the deformed body and moves relative to the fixed body by the action of a force or a moment.
The fixed body or the receiving body has a sensor-side concave portion housed in the mounting convex portion in a region facing the mounting object.
When the sensor-side concave portion accommodates the mounting convex portion, the inner peripheral surface of the sensor-side concave portion presses the mounting convex portion toward the inside of the sensor-side concave portion.

The acute angle formed by the inner peripheral surface of the sensor-side concave portion with respect to the mounting direction when the force sensor is mounted on the mounting object may be larger than the acute angle formed by the outer peripheral surface of the mounting convex portion with respect to the mounting direction. ..

Further, the mounting convex portions are provided so as to face each other at intervals when viewed from the mounting direction when the force sensor is mounted on the mounting object, or are continuously provided along a closed loop-shaped path. It may be provided intentionally or intermittently.

The force sensor according to the above tenth aspect and
A combination including an object to be attached to which the force sensor is attached is also within the scope of the present invention.

Alternatively, the force sensor according to the eleventh aspect of the present invention is attached to an object to be mounted having a mounting hole, and detects at least one of a force in each axial direction and a moment around each axis in the XYZ three-dimensional coordinate system. To do
Plasmodium that elastically deforms due to the action of force or moment
A fixed body connected to the deformed body and fixed with respect to XYZ three-dimensional coordinates,
It is provided with a receiving body that is connected to the deformed body and moves relative to the fixed body by the action of a force or a moment.
The fixed body or the force receiving body is provided with a through hole through which a fixture for mounting the force sensor is passed through the object to be mounted.
A protruding portion protruding toward the mounting object is provided on the edge of the through hole on the mounting object side.
The protruding portion presses the edge portion of the mounting hole when the force sensor is mounted on the mounting object.

In the force sensor according to the eleventh aspect described above, a mortar-shaped tapered surface on the mounting side is formed at the edge of the mounting hole.
A sensor-side tapered surface that tapers toward the object to be attached is formed on the outer peripheral surface of the protruding portion.
The sensor-side tapered surface presses the mounting-side tapered surface when the force sensor is mounted on the mounting object.
The acute angle formed by the sensor-side tapered surface with respect to the mounting direction when the force sensor is mounted on the mounting object may be smaller than the acute angle formed by the mounting-side tapered surface with respect to the mounting direction.

Alternatively, the force sensor according to the eleventh aspect described above and
A combination including an object to be attached to which the force sensor is attached is also within the scope of the present invention.

It is a schematic perspective view which shows the basic structure of the force sensor by one Embodiment of this invention. It is a schematic plan view which shows the basic structure of FIG. It is sectional drawing of [3]-[3] of FIG. It is an enlarged view of the rectangular region R shown by the alternate long and short dash line in FIG. It is a schematic plan view for demonstrating the elastic deformation which occurs in each deformation part when the moment + Mx around the X-axis acts on the basic structure of FIG. FIG. 5 is a schematic cross-sectional view of FIG. 6 (a) is a sectional view taken along line [6a]-[6a] of FIG. 5, and FIG. 6 (b) is a sectional view taken along line [6b]-[6b] of FIG. It is a schematic plan view for demonstrating the elastic deformation which occurs in each deformation part when the moment + My about the positive direction of Y axis acts on the basic structure of FIG. FIG. 7 is a schematic cross-sectional view of FIG. 8 (a) is a sectional view taken along line [8a]-[8a] of FIG. 7, and FIG. 8 (b) is a sectional view taken along line [8b]-[8b] of FIG. It is a schematic plan view for demonstrating the elastic deformation which occurs in each deformation part when the moment + Mz about the Z-axis forward acts on the basic structure of FIG. FIG. 9 is a schematic cross-sectional view of FIG. 10 (a) is a sectional view taken along line [10a]-[10a] of FIG. 9, and FIG. 10 (b) is a sectional view taken along line [10b]-[10b] of FIG. It is a schematic plan view for demonstrating the elastic deformation which occurs in each deformation part when the force + Fz in the positive direction of the Z axis acts on the basic structure of FIG. FIG. 11 is a schematic cross-sectional view of FIG. 12 (a) is a cross-sectional view taken along the line [12a]-[12a] of FIG. 11, and FIG. 12 (b) is a cross-sectional view taken along the line [12b]-[12b] of FIG. It is a schematic plan view which shows the force sensor using the basic structure of FIG. 13 is a cross-sectional view taken along the line [14]-[14] of FIG. It is a figure which shows the fluctuation of the capacitance value which occurs in each capacitance element when a force and a moment are applied to the force sensor of FIG. It is a schematic plan view which shows the basic structure of the force sensor by the 2nd Embodiment of this invention. 16 is a cross-sectional view taken along the line [17]-[17] of FIG. It is a schematic plan view which shows the deformed body of a rectangle. FIG. 18 is a schematic cross-sectional view of FIG. 19 (a) is a cross-sectional view taken along the line [19a]-[19a] of FIG. 18, and FIG. 19 (b) is a cross-sectional view taken along the line [19b]-[19b] of FIG. FIG. 3 is a schematic plan view of a square rectangular variant that can be used in the present invention. It is a schematic cross-sectional view of FIG. 21 (a) is a sectional view taken along the line [21a]-[21a] of FIG. 20, FIG. 21 (b) is a sectional view taken along the line [21b]-[21b] of FIG. ) Is a cross-sectional view taken along the line [21c]-[21c] of FIG. 20, and FIG. 21 (d) is a cross-sectional view taken along the line [21d]-[21d] of FIG. It is schematic cross-sectional view which shows the basic structure of the force sensor by this embodiment which adopted the rectangular deformed body of FIG. It is a figure for demonstrating the displacement which occurs at each detection point of the rectangular deformed body shown in FIG. 20 when the force + Fx in the positive direction of the X axis acts on a receiving body. It is a figure for demonstrating the displacement which occurs at each detection point of the rectangular deformed body shown in FIG. 20 when a force + Fz in the Z-axis positive direction acts on a receiving body. It is a figure for demonstrating the displacement which occurs at each detection point of the rectangular deformed body shown in FIG. 20 when the moment + Mx in the positive direction of the X-axis acts on a receiving body. FIG. 5 is a diagram for explaining the displacement generated at each detection point of the rectangular deformed body shown in FIG. 20 when a moment + Mz in the positive direction of the Z axis acts on the receiving body. A list shows the increase / decrease in the separation distance between each detection point of the rectangular deformed body and the fixed body in FIG. 20 when a force in each axial direction and a moment in each axial direction are applied to the receiving body in the XYZ three-dimensional coordinate system. It is a chart. FIG. 5 is a schematic plan view showing a force sensor according to the present embodiment using the basic structure of FIG. 22. It is sectional drawing of [29]-[29] of FIG. 28. It is a figure which shows the fluctuation of the capacitance value which occurs in each capacitance element when the force and the moment act on the force sensor of FIG. 28. It is a chart which shows the other axis sensitivity of the force in each axial direction and the moment around each axis in the force sensor 301c shown in FIG. 28 in a list. It is a schematic plan view which shows the basic structure adopted for the force sensor by the 4th Embodiment of this invention. A chart showing a list of increases and decreases in the distance between each detection point and the fixed body of the basic structure of FIG. 32 when a force in each axial direction and a moment in each axial direction are applied to the receiving body in the XYZ three-dimensional coordinate system. Is. It is a schematic plan view which shows the force sensor by the 4th Embodiment of this invention. It is a figure which shows the fluctuation of the capacitance value which occurs in each capacitance element when the force and the moment act on the force sensor of FIG. 34. It is a figure which shows the fluctuation of the capacitance value which occurs in each capacitive element when the force in each axial direction and the moment in each axial direction are applied to a receiving body. It is a chart which shows the other axis sensitivity of the force sensor of FIG. 34 calculated based on the fluctuation of each capacitance value shown in FIG. 36 in a list. It is a figure which shows the inverse matrix of the matrix corresponding to the other axis sensitivity shown in FIG. 37. It is a schematic side view which shows the deformed body by the modification of FIG. It is a schematic side view which shows the deformed body by the further modification of FIG. It is a schematic cross-sectional view which shows the combination of the force sensor by the modification of FIG. 1 and the attachment object to which this force sensor is attached. It is a schematic bottom view which shows the sensor side convex part of the force sensor shown in FIG. 41. It is a schematic low-view view showing another example of the mounting convex portion of the force sensor, and shows the mounting convex portion continuously provided along an annular path. It is a schematic low-view view showing another example of the mounting convex portion of the force sensor, and shows the mounting convex portion intermittently provided along an annular path. It is schematic cross-sectional view which shows the other combination with the force sensor by the modification of FIG. 1 and the attachment object to which this force sensor is attached. It is a figure for demonstrating an example of the manufacturing method of a deformed body, and is the schematic side view which shows the 2nd deformed part before the receiving part side curved part and the fixed part side curved part are formed. It is a figure for demonstrating an example of the manufacturing method of a deformed body, and is the schematic side view which shows the 2nd deformed part after the receiving part side curved part and the fixed part side curved part are formed. It is a schematic plan view which shows the modification of the basic structure of FIG. It is sectional drawing of [49]-[49] of FIG. 48. It is schematic cross-sectional view which shows the further modification example of the basic structure of FIG.

<<< §1. Force sensor according to the first embodiment of the present invention >>>
Hereinafter, the force sensor according to the first embodiment of the present invention will be described in detail with reference to the accompanying drawings.

<1-1. Basic structure ＞
FIG. 1 is a schematic perspective view showing a basic structure 1 of a force sensor according to the first embodiment of the present invention, FIG. 2 is a schematic plan view showing the basic structure 1 of FIG. 1, and FIG. 3 is a schematic plan view. , FIG. 2 is a cross-sectional view taken along the line [3]-[3] of FIG. In FIG. 2, the X-axis is defined in the left-right direction, the Y-axis is defined in the vertical direction, and the Z-axis (not shown) is defined in the depth direction. In the present specification, as shown in FIG. 1, the Z-axis positive direction is referred to as an upward direction, and the Z-axis negative direction is referred to as a downward direction. Regarding the direction of the moment, the X-axis positive rotation means the rotation direction in which the right-hand screw is rotated in order to advance the right-hand screw in the X-axis positive direction, and the X-axis negative rotation is the opposite rotation direction. To mean. The method of defining the direction of such a moment is the same for the Y-axis circumference and the Z-axis circumference.

As shown in FIGS. 1 to 3, the basic structure 1 moves relative to the disk-shaped fixed body 10 having an upper surface parallel to the XY plane and the fixed body 10 by being affected by a force and / or a moment. A disk-shaped receiving body 20 and an annular deformed body 40 connected to the fixed body 10 and the receiving body 20 and elastically deformed by the relative movement of the receiving body 20 with respect to the fixed body 10 are provided. .. The fixed body 10, the receiving body 20, and the deformed body 40 may be concentric with each other and have the same outer diameter. In addition, in FIG. 2, in order to clearly show the deformed body 40, the drawing of the receiving body 20 is omitted.

In the basic structure 1 according to the present embodiment, a capacitive element is arranged at a predetermined position in a gap formed between the deformed body 40 and the fixed body 10, and a predetermined detection circuit 50 is connected to the capacitive element. , Will function as a force sensor. The detection circuit 50 is for measuring the acting force and / or moment based on the amount of fluctuation of the capacitance value of the capacitive element. A specific arrangement mode of the capacitive element and a specific method for measuring the acting force or moment will be described later.

As shown in FIGS. 1 and 2, the deformed body 40 is arranged parallel to the XY plane with the origin O of the XYZ three-dimensional coordinate system as the center. Here, as shown in FIG. 3, it is assumed that the XY plane exists at a position half the thickness of the deformed body 40 in the Z-axis direction. As the material of the deformed body 40, for example, metal can be adopted.

As shown in FIG. 2, the deformed body 40 is located on the positive Y-axis with the first fixed portion 41 located on the positive X-axis and the second fixed portion 42 located on the negative X-axis. It has a first receiving unit 43 and a second receiving unit 44 located on the negative Y-axis. As will be described later, each of the fixed portions 41, 42 and each of the receiving portions 43, 44 is a region of the deformed body 40 to which the fixed body 10 and the receiving body 20 are connected, and is another region of the deformed body 40. It is not a site that has different characteristics from the region. Therefore, the materials of the fixed portions 41, 42 and the receiving portions 43, 44 are the same as those of the other regions of the deformed body 40. However, for convenience of explanation, the fixed portions 41, 42 and the receiving portions 43, 44 are illustrated with symbols different from those of the other regions of the deformed body 40.

Further, as shown in FIG. 2, the deformed body 40 has a first deformed portion 45 and a first deformed portion 45 located between the first fixed portion 41 and the first receiving portion 43 (first quadrant I of the XY plane). A second deformed portion 46 located between the receiving portion 43 and the second fixed portion 42 (second quadrant II of the XY plane) and between the second fixed portion 42 and the second receiving portion 44 (XY plane). A third deformed portion 47 located in the third quadrant III) of the above, and a fourth deformed portion 48 located between the second receiving portion 44 and the first fixed portion 41 (fourth quadrant IV of the XY plane). have. Both ends of the deformed portions 45 to 48 are integrally connected to the fixed portions 41 and 42 and the receiving portions 43 and 44, which are adjacent to each other along a closed loop-shaped path. With such a structure, the force or moment acting on the receiving force 43, 44 is surely transmitted to the deformed portions 45 to 48, whereby the elastic deformation corresponding to the applied force or moment is transmitted to each deformed portion 45. It is supposed to occur in ~ 48.

As shown in FIGS. 1 and 3, the basic structure 1 connects the first connecting member 31 and the second connecting member 32 that connect the fixed body 10 and the deformed body 40, and the receiving body 20 and the deformed body 40. It further has a third connecting member 33 and a fourth connecting member 34. The first connecting member 31 connects the lower surface of the first fixing portion 41 (lower surface in FIG. 3) and the upper surface of the fixed body 10 to each other, and the second connecting member 32 is fixed to the lower surface of the second fixing portion 42. The upper surface of the body 10 is connected to each other. The third connecting member 33 connects the upper surface of the first receiving portion 43 (upper surface in FIG. 3) and the lower surface of the receiving body 20 to each other, and the fourth connecting member 34 is the second receiving portion 44. The upper surface and the lower surface of the receiving body 20 are connected to each other. Each of the connecting members 31 to 34 has a rigidity that can be regarded as a substantially rigid body. Therefore, the force or moment acting on the receiving body 20 effectively causes elastic deformation in each of the deformed portions 45 to 48.

Next, with reference to FIG. 4, each of the deformed portions 45 to 48 of the deformed body 40 will be described in detail. Since each of the deformed portions 45 to 48 has the same structure as each other, only the second deformed portion 46 will be described here.

FIG. 4 is an enlarged view of the rectangular region R shown by the alternate long and short dash line in FIG. 3, and shows the second modified portion 46. The second deformed portion 46 connects the main curved portion 46p having the main curved surface 46pa curved in the negative direction of the Z axis (downward in FIG. 4), the main curved portion 46p, and the fixed portion 42, and connects the main curved portion 46p and the fixed portion 42 in the positive direction of the Z axis. A receiving force having a fixed portion-side curved surface 46fa curved in the Z-axis direction, connecting the main curved portion 46p and the receiving portion 43, and having a receiving portion-side curved surface 46ma curved in the Z-axis direction. It has a portion-side curved portion 46 m. As shown in FIG. 4, the main curved surface 46pa, the fixed portion side curved surface 46fa, and the receiving portion side curved surface 46ma both form a Z-axis negative side surface of the second deformed portion 46. In the present embodiment, the main curved surface 46pa is curved in the negative direction of the Z axis, whereas the curved surface 46fa on the fixed portion side and the curved surface 46ma on the receiving portion side are curved in the positive direction of the Z axis. It is curved.

More specifically, as shown in FIG. 4, the surface 46u on the Z-axis positive side of the second deformed portion 46 is a curved surface along an arc having a radius r1 centered on the point O1, and the second deformed portion 46. The main curved surface 46pa of 46 is a curved surface along an arc having a radius r2 centered on the point O2. Both of these curved surfaces 46u and 46pa are curved toward the negative side of the Z axis. The curved surface 46fa on the fixed portion side is a curved surface along an arc with a radius r3 centered on the point O3, and the curved surface 46ma on the receiving portion side is along an arc with a radius r4 centered on the point O4. It is a curved surface. These curved surfaces 46fa and 46ma are curved toward the positive side of the Z axis. In the illustrated example, the points O1 and O2 and the second measurement site A2 are arranged on a straight line parallel to the Z axis, and the relationship of r1 = r2 and r3 = r4 is established. Of course, it is not always necessary to satisfy such a relationship. Further, each of the curved surfaces 46u, 46pa, and 46ma is not limited to the shape along the arc of a perfect circle, and may have a shape along the arc of an ellipse or an oval, for example. This also applies to other embodiments and modifications described later.

Further, as shown in FIG. 4, in the second deformed portion 46, the fixed portion side curved portion 46f and the main curved portion 46p are smoothly connected via the fixed portion side inflection point Bf2, and further, the receiving force is received. The receiving portion side bending portion 46m and the main bending portion 46p are smoothly connected via the inflection point Bm2 on the portion side.

On the other hand, as shown in FIG. 4, the surface of the second deformed portion 46 on the positive side of the Z axis (upper surface in FIG. 4) is formed by a curved surface curved only in the negative direction of the Z axis. This curved surface has a constant radius of curvature in the present embodiment.

With the above configuration, when the second deformed portion 46 is observed along the closed loop path, the center of the path from the second fixed portion 42 to the first receiving portion 43 is the most negative side of the Z axis. Is located in. Then, as shown in FIG. 4, a second measurement portion A2 for detecting the elastic deformation occurring in the second deformation portion 46 is defined in the portion located on the most negative side. Therefore, the second deformed portion 46 is symmetrically configured with respect to the second measurement site A2 when observed along the closed loop path.

Further, although not shown, the first, third, and fourth deformed portions 45, 47, and 48 are also configured in the same manner as the second deformed portion 46. That is, the first, third, and fourth deformed portions 45, 47, and 48 include a fixed portion-side curved portion and a receiving portion-side curved portion having the curvature as described above, and a main curved portion sandwiched between them. have. The first, third, and fourth measurement sites are defined in the deformed portions 45, 47, and 48, respectively, in the respective portions located on the most negative side of the Z axis when observed along the closed loop path. ing. After all, as shown in FIG. 2, when the V-axis and the W-axis passing through the origin O and forming 45 ° with respect to the X-axis and the Y-axis are defined on the XY plane, the first deformed portion 45 has a positive V-axis. The second deformed portion 46 is symmetric with respect to the positive W axis, the third deformed portion 47 is symmetric with respect to the negative V axis, and the fourth deformed portion 48 is symmetric with respect to the negative W axis. Is. Then, the first to fourth measurement sites A1 to A4 of the deformed portions 46 to 48 are on the positive V-axis, the positive W-axis, the negative V-axis, and the negative V-axis when viewed from the Z-axis direction. They are located one by one.

<1-2. Action of basic structure ＞
Next, the operation of such a basic structure 1 will be described.

(1-2-1. When the moment Mx around the X axis acts on the basic structure 1)
FIG. 5 is a schematic plan view for explaining the elastic deformation that occurs in each of the deformed portions 45 to 48 when the moment + Mx around the X-axis is applied to the basic structure 1 of FIG. Further, FIG. 6 is a schematic cross-sectional view of FIG. 6 (a) is a sectional view taken along line [6a]-[6a] of FIG. 5, and FIG. 6 (b) is a sectional view taken along line [6b]-[6b] of FIG. In FIGS. 5 and 6, the thick black arrows indicate the acting force or moment, and the thick white arrows indicate the directions of displacement of the measurement sites A1 to A4. This also applies to other figures.

As shown in FIG. 5, when a moment + Mx around the X-axis is applied to the basic structure 1 via the receiving body 20 (see FIGS. 1 and 3), the first receiving portion 43 of the deformed body 40 is affected. A force in the Z-axis positive direction (upward in FIG. 6A) acts, and a force in the Z-axis negative direction (downward in FIG. 6B) acts on the second receiving portion 44. In FIG. 5, the symbol attached to the first receiving portion 43 and circled with a black dot indicates that the force acts from the negative direction of the Z axis to the positive direction of the Z axis, and the second receiving portion 43. The symbol with a cross circle attached to the force portion 44 indicates that the force acts from the positive direction of the Z axis to the negative direction of the Z axis. The meanings of these symbols are the same in FIGS. 7, 9 and 11.

At this time, as shown in FIGS. 6A and 6B, the following elastic deformations occur in the first to fourth deformed portions 45 to 48. That is, since the first receiving portion 43 moves upward by the force acting on the first receiving portion 43 in the positive direction of the Z axis, the first receiving portion of the first deformed portion 45 and the second deformed portion 46 The end connected to 43 is moved upward. As a result, as shown in FIG. 6A, the first deformed portion 45 and the second deformed portion 46 are generally upward except for the ends connected to the first and second fixed portions 41 and 42. Move to. That is, the first measurement site A1 and the second measurement site A2 both move upward. On the other hand, since the second receiving portion 44 moves downward due to the force acting on the second receiving portion 44 in the negative direction of the Z axis, the second receiving portion of the third deformed portion 47 and the fourth deformed portion 48 The end connected to 44 is moved downward. As a result, as shown in FIG. 6B, the third deformed portion 47 and the fourth deformed portion 48 are generally downward except for the ends connected to the first and second fixed portions 41 and 42. Move to. That is, the third measurement site A3 and the fourth measurement site A4 both move downward.

Such movement is represented in FIG. 5 by adding a circled “+” or “−” symbol to each of the measurement sites A1 to A4. That is, the measurement part marked with the black dot circled is displaced in the positive direction of the Z axis due to the elastic deformation of the deformed part, and the measurement part marked with the cross circled is the deformed part. It is displaced in the negative direction of the Z axis due to elastic deformation. This also applies to FIGS. 7, 9 and 11.

After all, when the moment + Mx around the X-axis forward acts on the receiving body 20 of the basic structure 1, the separation distance between the first and second measurement sites A1 and A2 and the upper surface of the fixed body 10 (see FIG. 3) is increased. , Both increase, and the distance between the third and fourth measurement sites A3, A4 and the upper surface of the fixed body 10 decreases together.

Although not shown, when the moment-Mx around the negative axis of the X axis acts on the receiving body 20 of the basic structure 1, the moving direction of each of the measurement sites A1 to A4 is opposite to the above-described direction. That is, the distance between the first and second measurement sites A1 and A2 and the upper surface of the fixed body 10 (see FIG. 2) is reduced by the action of the moment −Mx around the negative axis of the X axis, and the third and fourth measurement sites are reduced. The distance between the measurement sites A3 and A4 and the upper surface of the fixed body 10 increases together.

(1-2-2. When a moment My around the Y axis acts on the basic structure 1)
FIG. 7 is a schematic plan view for explaining the elastic deformation that occurs in each of the deformed portions 45 to 48 when the moment + My in the normal direction of the Y axis acts on the basic structure 1 of FIG. Further, FIG. 8 is a schematic cross-sectional view of FIG. 7. 8 (a) is a sectional view taken along line [8a]-[8a] of FIG. 7, and FIG. 8 (b) is a sectional view taken along line [8b]-[8b] of FIG.

As shown in FIGS. 7 and 8, when a moment + My in the positive direction of the Y axis acts on the basic structure 1 via the receiving body 20 (see FIGS. 1 and 3), the first and first deformed bodies 40 2 A force in the positive direction of the Z axis acts on the region on the negative side of the X axis of the receiving portions 43 and 44, and the negative direction of the Z axis acts on the region on the positive side of the X axis of the first and second receiving portions 43 and 44. The force of

At this time, as shown in FIGS. 8A and 8B, the following elastic deformations occur in the first to fourth deformed portions 45 to 48. That is, the region on the positive side of the X-axis moves downward due to the force in the negative direction of the Z-axis acting on the positive side of the X-axis (the right side in FIG. 8A) of the first receiving portion 43, so that the first deformed portion Of the 45, the end connected to the first receiving portion 43 is moved downward. As a result, as shown in FIG. 8A, the first deformed portion 45 moves downward as a whole except for the end portion connected to the first fixed portion 41. That is, the first measurement site A1 moves downward. On the other hand, since the region on the negative side of the X-axis moves upward due to the force in the positive direction of the Z-axis acting on the negative side of the X-axis of the first receiving portion 43 (the left side in FIG. 8A), the second deformed portion Of the 46, the end connected to the first receiving portion 43 moves upward. As a result, as shown in FIG. 8A, the second deformed portion 46 moves upward as a whole except for the end portion connected to the second fixed portion 42. That is, the second measurement site A2 moves upward.

Further, as shown in FIG. 8B, the region on the negative side of the X-axis is caused by the force in the positive direction of the Z-axis acting on the negative side of the X-axis of the second receiving portion 44 (the right side in FIG. 8B). In order to move upward, the end portion of the third deformed portion 47 connected to the second receiving portion 44 is moved upward. As a result, as shown in FIG. 8B, the third deformed portion 47 moves upward as a whole except for the end portion connected to the second fixed portion 42. That is, the third measurement site A3 moves upward.

On the other hand, as shown in FIG. 8B, the region on the positive side of the X-axis is caused by the force in the negative direction of the Z-axis acting on the positive side of the X-axis of the second receiving portion 44 (the left side in FIG. 8B). Since it moves downward, the end portion of the fourth deformed portion 48 connected to the second receiving portion 44 is moved downward. As a result, as shown in FIG. 8B, the fourth deformed portion 48 moves downward as a whole except for the end portion connected to the first fixed portion 41. That is, the fourth measurement site A4 moves downward.

After all, when the moment + My in the normal direction of the Y axis acts on the receiving body 20 of the basic structure 1, the separation distance between the first and fourth measurement sites A1 and A4 and the upper surface of the fixed body 10 (see FIG. 3) is increased. , Both decrease, and the distance between the second and third measurement sites A2, A3 and the upper surface of the fixed body 10 increases together.

Although not shown, when the moment-My around the negative axis of the Y axis acts on the receiving body 20 of the basic structure 1, the moving directions of the measurement sites A1 to A4 are opposite to the above-described directions. That is, the distance between the first and fourth measurement sites A1 and A4 and the upper surface of the fixed body 10 (see FIG. 3) is increased by the action of the moment-My around the negative Y-axis, and the second and third measurement sites are both increased. The distance between the measurement sites A2 and A3 and the upper surface of the fixed body 10 is reduced.

(1-2-3. When a moment Mz around the Z axis acts on the basic structure 1)
FIG. 9 is a schematic plan view for explaining the elastic deformation that occurs in each of the deformed portions 45 to 48 when the moment + Mz in the normal direction of the Z axis acts on the basic structure 1 of FIG. Further, FIG. 10 is a schematic cross-sectional view of FIG. 10 (a) is a sectional view taken along line [10a]-[10a] of FIG. 9, and FIG. 10 (b) is a sectional view taken along line [10b]-[10b] of FIG.

As shown in FIG. 9, when a moment + Mz in the positive direction of the Z axis acts on the basic structure 1 via the receiving body 20 (see FIGS. 1 and 3), the first receiving portion 43 of the deformed body 40 is affected. On the other hand, a force in the negative direction of the X axis (left direction in FIG. 9) acts, and a force in the positive direction of the X axis (right direction in FIG. 9) acts on the second receiving portion 44.

At this time, as shown in FIGS. 10A and 10B, the following elastic deformations occur in the first to fourth deformed portions 45 to 48. That is, since the first receiving portion 43 moves in the negative direction of the X axis due to the force acting on the first receiving portion 43 in the negative direction of the X axis, the first deformed portion 45 is pulled along the X axis direction. Force acts. As a result, the first main bending portion 45p is elastically deformed so that the radius of curvature becomes large while maintaining the Z coordinate values of both ends thereof. That is, the first measurement site A1 moves upward. On the other hand, when the first receiving portion 43 moves in the negative direction of the X-axis, a compressive force along the X-axis direction acts on the second deformed portion 46. As a result, the second main bending portion 46p is elastically deformed so that the radius of curvature becomes smaller while maintaining the Z coordinate values of both ends thereof. That is, the second measurement site A2 moves downward.

Further, since the second receiving portion 44 moves in the X-axis positive direction by the force acting on the second receiving portion 44 in the X-axis positive direction, the third deformed portion 47 has a tensile force along the X-axis direction. Works. As a result, the third main bending portion 47p is elastically deformed so that the radius of curvature becomes large while maintaining the Z coordinate values of both ends thereof. That is, the third measurement site A3 moves upward. On the other hand, when the second receiving portion 44 moves in the positive direction of the X-axis, a compressive force along the X-axis direction acts on the fourth deformed portion 48. As a result, the fourth main bending portion 48p is elastically deformed so that the radius of curvature becomes smaller while maintaining the Z coordinate values of both ends thereof. That is, the fourth measurement site A4 moves downward.

After all, when the moment + Mz around the Z-axis forward acts on the receiving body 20 of the basic structure 1, the separation distance between the first and third measurement sites A1 and A3 and the upper surface of the fixed body 10 increases together. The distance between the second and fourth measurement sites A2 and A4 and the upper surface of the fixed body 10 (see FIG. 2) is reduced.

Although not shown, when a moment −Mz around the negative axis of the Z axis acts on the receiving body 20 of the basic structure 1, the moving direction of each of the measurement sites A1 to A4 is opposite to the above-described direction. That is, the distance between the first and third measurement sites A1 and A3 and the upper surface of the fixed body 10 is reduced by the action of the moment −Mz around the negative axis of the Z axis, and the second and fourth measurement sites A2 and A4 are both reduced. The distance between the fixed body 10 and the upper surface of the fixed body 10 (see FIG. 2) increases.

(1-2-4. When a force Fz in the Z direction acts on the basic structure 1)
Next, FIG. 11 is a schematic plan view for explaining the elastic deformation that occurs in each of the deformed portions 45 to 48 when a force + Fz in the positive direction of the Z axis acts on the basic structure 1 of FIG. Further, FIG. 12 is a schematic cross-sectional view of FIG. 12 (a) is a cross-sectional view taken along the line [12a]-[12a] of FIG. 11, and FIG. 12 (b) is a cross-sectional view taken along the line [12b]-[12b] of FIG.

As shown in FIGS. 11 and 12, when a force + Fz in the positive direction of the Z axis acts on the basic structure 1 via the receiving body 20 (see FIGS. 1 and 3), the first and first deformed bodies 40 2 A force in the positive direction of the Z axis acts on the receiving portions 43 and 44.

At this time, as shown in FIGS. 12A and 12B, the following elastic deformations occur in the first to fourth deformed portions 45 to 48. That is, since each of the receiving portions 43 and 44 moves upward by the force in the positive direction of the Z axis acting on the first and second receiving portions 43 and 44, the first and second of the deformed portions 45 to 48 Each end connected to the receiving portions 43 and 44 is moved upward. As a result, as shown in FIGS. 11 (a) and 11 (b), the measurement sites A1 to A4 move upward.

After all, when a force + Fz in the positive direction of the Z axis acts on the receiving body 20 of the basic structure 1, the separation distance between the first to fourth measurement sites A1 to A4 and the upper surface of the fixed body 10 (see FIG. 2) is increased. , All increase.

Although not shown, when a force −Fz in the negative Z-axis direction acts on the receiving body 20 of the basic structure 1, the moving direction of each of the measurement sites A1 to A4 is opposite to the above-described direction. That is, the distance between the first to fourth measurement sites A1 to A4 and the upper surface of the fixed body 10 (see FIG. 2) is all reduced by the action of the force −Fz in the negative direction of the Z axis.

<1-3. Capacitive element type force sensor ＞
(1-3-1. Configuration of force sensor)
§1-1. And §1-2. The basic structure 1 described in detail in the above can be suitably used as a capacitive element type force sensor 1c. Here, such a force sensor 1c will be described in detail below.

FIG. 13 is a schematic plan view showing a force sensor 1c using the basic structure 1 of FIG. 1, and FIG. 14 is a sectional view taken along line [14]-[14] of FIG. In FIG. 14, in order to clearly show the deformed body 40, the drawing of the receiving body 20 is omitted.

As shown in FIGS. 13 and 14, the force sensor 1c is configured by arranging one capacitive element C1 to C4 at each of the measurement sites A1 to A4 of the basic structure 1 of FIG. Specifically, as shown in FIG. 14, the force sensor 1c is arranged on the fixed body 10 so as to face the first displacement electrode Em1 arranged at the first measurement site A1 and the first displacement electrode Em1. It has a first fixed electrode Ef1 that does not move relative to each other. These electrodes Em1 and Ef1 constitute the first capacitance element C1. Further, as shown in FIG. 14, the force sensor 1c is arranged to face the second displacement electrode Em2 and the second displacement electrode Em2 arranged at the second measurement site A2, and is relative to the fixed body 10. It has a second fixed electrode Ef2 that does not move. These electrodes Em2 and Ef2 constitute a second capacitance element C2.

Although not shown, the force sensor 1c is arranged so as to face the third displacement electrode Em3 arranged at the third measurement site A3 and the third displacement electrode Em3, and does not move relative to the fixed body 10. 3 Fixed electrode Ef3, 4th displacement electrode Em4 arranged at the 4th measurement site A4, 4th fixed electrode Ef4 arranged facing the 4th displacement electrode Em4 and not moving relative to the fixed body 10. have. The electrode Em3 and the electrode Ef3 constitute the third capacitance element C3, and the electrode Em4 and the electrode Ef4 constitute the fourth capacitance element C4.

Specifically, as shown in FIG. 14, the displacement electrodes Em1 to Em4 are placed on the lower surfaces of the first to fourth deformed body side supports 61 to 64 supported by the corresponding measurement sites A1 to A4, from the first to the first. It is supported via the fourth displacement substrates Im1 to Im4. Further, the fixed electrodes Ef1 to Ef4 are supported on the upper surfaces of the first to fourth fixed body side supports 71 to 74 fixed to the upper surface of the fixed body 10 via the first to fourth fixed substrates If1 to If4. ing. The displacement electrodes Em1 to Em4 all have the same area, and the fixed electrodes Ef1 to Ef4 also have the same area. However, as a device for maintaining a constant value of the effective facing areas of the capacitive elements C1 to C4 by the action of a force and / or a moment, the electrode areas of the displacement electrodes Em1 to Em4 are set to the fixed electrodes Ef1 to Ef4. It is configured to be larger than the electrode area of. This point will be described in detail later. In the initial state, the effective facing areas and separation distances of the electrodes of each set constituting the capacitive elements C1 to C4 are all the same.

Further, as shown in FIGS. 13 and 14, the force sensor 1c is an electric signal indicating a force and a moment acting on the receiving body 20 based on the elastic deformation generated in each of the deformed portions 45 to 48 of the deformed body 40. It has a detection circuit 50 that outputs. In FIGS. 13 and 14, the wiring for electrically connecting the capacitance elements C1 to C4 and the detection circuit 50 is not shown.

When the fixed body 10, the receiving body 20 and the deformed body 40 are made of a conductive material such as metal, the first to fourth displacement substrates Im1 to Im4 and the first to first ones are prevented so that the electrodes are not short-circuited. 4 The fixed substrates If1 to If4 need to be composed of an insulator.

(1-3-2. Fluctuation of capacitance value of each capacitive element when moment Mx around the X axis acts on the force sensor 1c)
Next, FIG. 14 is a chart showing fluctuations in capacitance values that occur in the capacitance elements C1 to C4 when a force and a moment are applied to the force sensor 1c of FIG.

First, when the moment + Mx around the X-axis acts on the force sensor 1c according to the present embodiment, it is understood from the behavior of each measurement part A1 to A4 described in §1-2-1. , The separation distance between the electrodes constituting the first capacitance element C1 and the second capacitance element C2 both increases. Therefore, the capacitance values of the first capacitance element C1 and the second capacitance element C2 both decrease. On the other hand, the separation distance between the electrodes constituting the third capacitance element C3 and the fourth capacitance element C4 both decreases. Therefore, the capacitance values of the third capacitance element C3 and the fourth capacitance element C4 both increase. The fluctuations in the capacitance values of the capacitance elements C1 to C4 are collectively shown in the column of "Mx" in FIG. In this chart, "+" indicates that the capacitance value increases, and "-" indicates that the capacitance value decreases. When the moment-Mx around the negative axis of the X axis acts on the force sensor 1c, the fluctuation of the capacitance value of each of the capacitance elements C1 to C4 is opposite to the above-mentioned fluctuation (in the column of Mx in FIG. 15). All the symbols shown are reversed).

(1-3-3. Fluctuation of capacitance value of each capacitance element when moment My around Y axis acts on force sensor 1c)
Next, when the moment + My around the Y-axis positively acts on the force sensor 1c according to the present embodiment, it can be understood from the behavior of each measurement part A1 to A4 described in §1-2-2. In addition, the separation distance between the electrodes constituting the first capacitance element C1 and the fourth capacitance element C4 is reduced. Therefore, the capacitance values of the first capacitance element C1 and the fourth capacitance element C4 both increase. On the other hand, the separation distance between the electrodes constituting the second capacitance element C2 and the third capacitance element C3 both increases. Therefore, the capacitance values of the second capacitance element C2 and the third capacitance element C3 both decrease. The fluctuations in the capacitance values of the capacitance elements C1 to C4 are collectively shown in the column of "My" in FIG. When a moment-My around the negative axis of the Y axis acts on the force sensor 1c, the fluctuation of the capacitance value of each of the capacitance elements C1 to C4 is opposite to the above-mentioned fluctuation (in the column of My in FIG. 15). All the symbols shown are reversed).

(1-3-4. Fluctuation of capacitance value of each capacitive element when moment Mz around Z axis acts on force sensor 1c)
Next, when the moment + Mz around the Z-axis positively acts on the force sensor 1c according to the present embodiment, it can be understood from the behavior of each measurement site A1 to A4 described in §1-2-3. In addition, the separation distance between the electrodes constituting the first capacitance element C1 and the third capacitance element C3 both increases. Therefore, the capacitance values of the first capacitance element C1 and the third capacitance element C3 both decrease. On the other hand, the separation distance between the electrodes constituting the second capacitance element C2 and the fourth capacitance element C4 both decreases. Therefore, the capacitance values of the second capacitance element C2 and the fourth capacitance element C4 both increase. The fluctuations in the capacitance values of the capacitance elements C1 to C4 are collectively shown in the column of "Mz" in FIG. When a moment −Mz around the negative axis of the Z axis acts on the force sensor 1c, the fluctuation of the capacitance value of each of the capacitance elements C1 to C4 is opposite to the above-mentioned fluctuation (in the column of Mz in FIG. 15). All the symbols shown are reversed).

(1-3-5. Fluctuation of capacitance value of each capacitive element when force Fz in the Z-axis direction acts on the force sensor 1c)
Next, when a force + Fz in the positive direction of the Z axis acts on the force sensor 1c according to the present embodiment, it can be understood from the behavior of each measurement site A1 to A4 described in §1-2-4. In addition, the separation distance between the electrodes constituting the capacitive elements C1 to C4 is all increased. Therefore, the capacitance values of the capacitive elements C1 to C4 are all reduced. The fluctuations in the capacitance values of the capacitance elements C1 to C4 are collectively shown in the column of "Fz" in FIG. When a force −Fz in the negative direction of the Z axis acts on the force sensor 1c, the fluctuation of the capacitance value of each of the capacitance elements C1 to C4 is opposite to the above-mentioned fluctuation (in the column of Fz in FIG. 15). All the symbols shown are reversed).

(1-3-6. Calculation method of applied force and moment)
In view of the fluctuation of the capacitance value of the capacitance elements C1 to C4 as described above, the detection circuit 50 uses the following [Equation 1] to generate the moments Mx, My, Mz and the force Fz acting on the force sensor 1c. calculate. In [Equation 1], C1 to C4 indicate the amount of fluctuation in the capacitance value of the first to fourth capacitance elements C1 to C4.
[Equation 1]
Mx = -C1-C2 + C3 + C4
My = C1-C2-C3 + C4
Mz = -C1 + C2-C3 + C4
Fz =-(C1 + C2 + C3 + C4)

When the force and moment acting on the force sensor 1c are in the negative direction, Mx, My, Mz and Fz on the left side may be set to -Mx, -My, -Mz and -Fz. However, in this case, since the signs of C1 to C4 on the right side are also reversed, the force and moment acted by [Equation 1] are measured regardless of the sign of the acting force and moment.

According to the force sensor 1c according to the present embodiment as described above, the fixed portion side curved portion 45f is formed between the main curved portions 45p to 48p and the fixed portions 41, 42 and the receiving portions 43, 44 adjacent thereto. By interposing ~ 48f and the receiving portion side bending portions 45m to 48m, respectively, stress concentration on the connecting portion between the main bending portions 45p to 48p and the fixing portions 41, 42 and the receiving portions 43, 44 adjacent thereto. Can be avoided. Therefore, according to the present embodiment, a capacitance type force sensor 1c having high reliability can be provided.

Further, the force sensor 1c includes a fixed body 10 fixed to the XYZ three-dimensional coordinate system, and a receiving body 20 that moves relative to the fixed portions 41 and 42 by the action of a force and / or a moment. The fixed portions 41 and 42 of the deformed body 40 are connected to the fixed body 10, and the receiving portions 43 and 44 of the deformed body 40 are connected to the receiving body 20. Therefore, it is easy to apply a force and a moment to the deformed body 40.

Further, since the fixed body 10 and the force receiving body 20 are formed with through holes through which the Z axis is inserted, the force sensor 1c can be reduced in weight and the force sensor 1c can be freely installed. You can also increase the degree.

In the force sensor 1c according to the present embodiment, when the V-axis and the W-axis that pass through the origin O and form 45 ° with respect to the X-axis and the Y-axis are defined on the XY plane, four sets of capacitive elements C1 to C4 are defined. Are arranged one by one at four portions overlapping the V-axis and the W-axis when viewed from the Z-axis direction. Therefore, since the capacitance elements C1 to C4 are arranged symmetrically with respect to the X-axis and the Y-axis, the capacitance values of the capacitance elements C1 to C4 fluctuate with high symmetry. Therefore, the acting force and moment can be measured extremely easily based on the fluctuation amount of the capacitance value of the capacitance elements C1 to C4.

In the above description, the four capacitive elements C1 to C4 have separate fixed substrates If1 to If4 and individual fixed electrodes Ef1 to Ef4. However, in other embodiments, the fixed substrate may be configured to be common to the four capacitive elements, and individual fixed electrodes may be provided on the fixed substrate. Alternatively, the fixed substrate and the fixed electrode may be configured to be common to the four capacitive elements. With such a configuration, the force and the moment can be measured in the same manner as the force sensor 1c described above. It should be noted that these configurations also hold in each of the embodiments described later.

Further, the force sensor 1c changes its sensitivity to the acting force and moment by changing the cross-sectional shape of the deformed body 40. Specifically, it is as follows. That is, in the present embodiment, the cross-sectional shape of the deformed body 40 in the radial direction is square (see FIG. 3), but if this cross-sectional shape is made into a vertically long rectangle long in the Z-axis direction, it is around the X and Y axes. The sensitivity to the moments Mx, My and the force Fz in the Z-axis direction is relatively lower than the sensitivity to the moment Mz around the Z-axis. On the other hand, if the cross-sectional shape of the deformed body 40 is a horizontally long rectangle that is long in the radial direction of the deformed body 40, the moments around the X and Y axes Mx, My and the forces in the Z axis direction are opposite to the previous case. The sensitivity to Fz is relatively higher than the sensitivity to the moment Mz around the Z axis.

Alternatively, the force sensor 1c is also sensitive to the acting force and moment by changing the radius of curvature (degree of curvature) of the main bending portions 45p to 48p. Specifically, when the radius of curvature of the main curved portions 45p to 48p is reduced (the degree of curvature is increased), the sensitivity to the acting force and moment increases. On the other hand, if the radius of curvature of the main curved portions 45p to 48p is increased (the degree of curvature is decreased), the sensitivity to the acting force and moment decreases.

By considering the relationship between the cross-sectional shape of the deformed body 40, the radius of curvature of the main curved portions 45p to 48p, and the sensitivity to forces and moments, the sensitivity of the force sensor 1c is optimized for the usage environment. Can be transformed into. Of course, the above description also holds for each embodiment described later.

<<< §2. Force sensor according to the second embodiment of the present invention >>>
Next, the force sensor 201c according to the second embodiment of the present invention will be described.

FIG. 16 is a schematic plan view showing the basic structure 201 of the force sensor 201c according to the second embodiment of the present invention, and FIG. 17 is a sectional view taken along line [17]-[17] of FIG.

As shown in FIGS. 16 and 17, the structure of the fixed body 210 and the receiving body 220 of the basic structure 201 is different from the basic structure 1 of the force sensor 1c according to the first embodiment. Specifically, both the fixed body 210 and the receiving body 220 of the basic structure 201 have an annular (cylindrical) shape. Then, as shown in FIGS. 16 and 17, the fixed body 210 is arranged inside the deformed body 40 and the receiving body 220 is arranged outside the deformed body 40 when viewed from the Z-axis direction. .. The central axes of the fixed body 210, the receiving body 220, and the deformed body 40 all overlap with the Z axis and are concentric with each other. Of course, the fixed body 210 may be arranged outside the deformed body 40, and the receiving body 220 may be arranged inside the deformed body 40.

As shown in FIG. 17, the receiving body 220 has a receiving body surface 220a facing in the negative direction (downward) of the Z axis. Further, the fixed body 210 has a fixed body surface 210a facing in the negative direction (downward) of the Z axis. Both the receiving body surface 220a and the fixed body surface 210a are planes parallel to the XY plane. Further, the deformed body 40 has the same downward-facing deformed body surface 40a as the receiving body surface 220a. In the present embodiment, as shown in FIG. 17, the Z coordinate of the receiving body surface 220a, the Z coordinate of the fixed body surface 210a, and the Z coordinate of the deformed body surface 40a are different from each other. More specifically, the Z coordinate of the fixed body surface 210a is smaller than the Z coordinate of the deformed body surface 40a, and the Z coordinate of the deformed body surface 40a is smaller than the Z coordinate of the receiving body surface 220a. Here, the Z coordinate of the deformed body surface 40a means the coordinate having the largest absolute value of the Z coordinate among the deformed body surface 40a. Therefore, the Z coordinate of the deformed body surface 40a of the present embodiment is the Z coordinate of the measurement sites A1 to A4. In another embodiment, only one of the coordinates of the receiving body surface 220aZ and the Z coordinates of the fixed body surface 210a may be different from the Z coordinates of the deformed body surface 40a.

With the arrangement of the fixed body 210, the receiving body 220, and the deformed body 40 as described above, the arrangement of the first to fourth connecting members 231 to 234 is also different from the force sensor 1c according to the first embodiment. ing. That is, as shown in FIGS. 16 and 17, the first connecting member 231 has an outer surface of the fixed body 210 (a side surface facing the positive direction of the X axis) and an inner surface surface of the deformed body 40 on the positive X axis. (The side surface facing the negative direction of the X-axis) is connected. On the other hand, the second connecting member 232 has an outer surface of the fixed body 210 (a side surface facing the negative direction of the X axis) and an inner surface surface of the deformed body 40 (a side surface facing the positive direction of the X axis) on the negative X axis. Is connected to. Further, as shown in FIG. 16, on the positive Y-axis, the inner side surface of the receiving body 220 (the side surface facing the negative direction of the Y-axis) and the outer surface of the deformed body 40 (the side surface facing the positive direction of the Y-axis). Is connected by a third connecting member 233, and on the negative Y-axis, the inner side surface of the receiving body 220 (the side surface facing the positive direction of the Y-axis) and the outer surface of the deformed body 40 (in the negative direction of the Y-axis). The facing side surface) is connected by a fourth connecting member 234. Other configurations are the same as the basic structure 1 of the force sensor 1c according to the first embodiment. Therefore, in the drawings, the corresponding components are designated by the same reference numerals, and detailed description thereof will be omitted.

Although not shown, the force sensor 201c is formed by arranging four capacitive elements in the same arrangement as the force sensor 1c according to the first embodiment with respect to the basic structure 201 as described above. It is composed. Although the member for arranging the fixed electrode is not shown in FIG. 17, the fixed electrode may be appropriately arranged at the portion where the force sensor 201c is attached, or is additionally attached to the fixed body 210. A member may be fixed and a fixed electrode may be arranged on the member.

The force sensor 201c as described above can be suitably installed in a mechanical portion composed of a first member and a second member that move relative to each other, such as a joint of a robot. That is, if the fixed body 210 is connected to the first member and the force receiving body 220 is connected to the second member, the force sensor 201c is arranged in a limited space so as not to interfere with other members. be able to.

Since the method for measuring the force and the moment acting on the force sensor 201c is the same as that of the force sensor 1c according to the first embodiment, detailed description thereof will be omitted here.

In the basic structure 201 as described above, the receiving body 220, the deformed body 40, and the fixed body 210 are arranged concentrically and along the XY plane. Therefore, each component of the basic structures 201 and 202 can be integrally formed by cutting. By such processing, it is possible to provide a force sensor 201c without hysteresis.

<<< §3. Modifications of §1 and §2 >>>
Next, with reference to FIGS. 18 and 19, a modified example of the modified body 640 applicable to the force sensor 1c and 201c according to each of the above embodiments will be described.

The annular deformed body 40 shown in FIG. 2 is a donut-shaped structure in which both the inner peripheral contour and the outer peripheral contour are circular, but the annular deformed body used in the present invention does not necessarily have to be circular and is elliptical. It may be a structure having an arbitrary shape such as a shape, a rectangle shape, or a triangle shape. In short, any annular plasmodium having any shape may be used as long as it is a structure along a closed loop path.

FIG. 18 is a schematic plan view showing a rectangular variant 640. 19A is a schematic cross-sectional view of FIG. 18, FIG. 19A is a sectional view taken along the line [19a]-[19a] of FIG. 18, and FIG. 19B is a sectional view taken along the line [19b] of FIG. ]-[19b] is a cross-sectional view taken along the line.

The modified body 640 according to this modified example has a rectangular shape as a whole. Here, as shown in FIG. 18, a square variant 640 will be described as an example. The deformed body 640 includes a first fixed portion 641 located on the positive X-axis, a second fixed portion 642 located on the negative X-axis, and a first receiving portion 643 located on the positive Y-axis. It has a second receiving portion 644 located on the negative Y-axis. The fixed portions 641 and 642 and the receiving portions 643 and 644 are regions in the deformed body 640 to which the fixed body 10 and the receiving body 20 are connected, and have different characteristics from the other regions of the deformed body 640. Not a part. Therefore, the materials of the fixed portions 641 and 642 and the receiving portions 643 and 644 are the same as those of the other regions of the deformed body 640.

As shown in FIG. 18, the deformed body 640 further includes a first deformed portion 645 located between the first fixed portion 641 and the first receiving portion 643 (first quadrant of the XY plane) and a first receiving portion. A second deformed portion 646 located between the force portion 643 and the second fixed portion 642 (the second quadrant of the XY plane) and between the second fixed portion 642 and the second receiving portion 644 (the second of the XY plane). It has a third deformed portion 647 located in (three quadrants) and a fourth deformed portion 648 located between the second receiving portion 644 and the first fixed portion 641 (fourth quadrant of the XY plane). There is. Both ends of each of the deformed portions 645 to 648 are integrally connected to the adjacent fixed portions 641 and 642 and the receiving portions 643 and 644, respectively. With such a structure, the force and moment acting on the receiving portions 43 and 44 are surely transmitted to each deforming portion 645 to 648, whereby the elastic deformation corresponding to the applied force and moment is transmitted to each deforming portion 645. It is supposed to occur at ~ 648.

As shown in FIG. 19, the first to fourth deformed portions 645 to 648 are all formed in a straight line when viewed from the Z-axis direction. Further, since the distances from the origin O to the fixed portions 641 and 642 and the receiving portions 643 and 644 are all equal, the deformed portions 645 to 648 are arranged so as to form one side of the square.

Further, as shown in FIGS. 19 (a) and 19 (b), each of the deformed portions 645 to 648 of the deformed body 640 has a structure similar to that of the deformed portions 45 to 48 described in §1. .. However, in the modified body 640 of this modified example, each of the deformed portions 645 to 648 is formed in a linear shape instead of an arc shape when viewed from the Z-axis direction. In this modified example as well, since the first deformed portion 645 is symmetrically configured with respect to the positive V axis, the portion located at the lowermost position (Z-axis negative direction) of the first main curved portion 645p is the positive V axis. Exists on.

Such a configuration is also adopted in the remaining three deformed portions 646, 647, and 648. That is, the second deformed portion 646 has a portion located at the lowermost position of the second main curved portion 646p on the positive W axis and has a symmetrical shape with respect to the positive W axis. .. The third deformed portion 647 has a portion located at the lowermost portion of the third main curved portion 647p on the negative V-axis and has a shape symmetrical with respect to the negative V-axis. The fourth deformed portion 648 has a portion located at the lowermost position of the fourth main curved portion 648p on the negative W axis and has a symmetrical shape with respect to the negative V axis.

As shown in FIGS. 19A and 19B, each of the deformed bodies 640 is located at the lowermost portion of the first to fourth main bending portions 645p to 648p, that is, when viewed from the Z-axis direction. At the lower part of the portion where the main bending portions 645p to 648p overlap the V-axis and the W-axis, measurement portions A1 to A4 for detecting elastic deformation occurring in each deformation portion 645 to 648 are defined. In FIG. 18, the measurement sites A1 to A4 are shown to be provided on the upper surface (front side surface) of the deformed body 640, but in reality, they are provided on the lower surface (back side surface) of the deformed body 640. It is provided (see FIG. 19).

After all, the deformed body 640 is the annular deformed body 40 of the force sensor 1c and 201c described in §1 and §2, in which only the overall shape is changed to a rectangle while substantially maintaining the structure of each deformed part. It can be said that. Therefore, even if the annular deformed body 40 of the force sensor 1c and 201c is replaced with the above-mentioned deformed body 640, the same effect as that of the force sensor 1c and 201c can be obtained.

<<< §4. Force sensor according to the third embodiment of the present invention >>>
Next, the force sensor according to the third embodiment of the present invention will be described in detail.

<4-1. Structure of basic structure ＞
FIG. 20 is a plan view of a square rectangular variant 340 that can be used in the present invention. 21 (a) is a cross-sectional view taken along the line [21a]-[21a] of FIG. 20, and FIG. 21 (b) is a cross-sectional view taken along the line [21b]-[21b] of FIG. (C) is a cross-sectional view taken along the line [21c]-[21c] of FIG. 20, and FIG. 21 (d) is a cross-sectional view taken along the line [21d]-[21d] of FIG. The rectangular deformed body 340 of the present embodiment is a structure in which both the inner peripheral contour and the outer peripheral contour form a square, and when viewed from the Z-axis direction, each side is centered on the origin O and each side is on the X-axis or the Y-axis. They are arranged in parallel. The rectangular deformed body 340 has four fixed portions 341a to 341d fixed with respect to the XYZ three-dimensional coordinate system along a square closed loop-shaped path, and fixed portions 341a to 341a in the closed loop-shaped path of the rectangular deformed body 340. Four receiving parts 343a to 343d, which are positioned alternately with 341d and are affected by forces and moments, and one between the fixed parts 341a to 341d and the receiving parts 343a to 343d adjacent to each other in a closed loop path. It has a total of eight deformed portions 345A to 345H, which are positioned one by one.

Specifically, as shown in FIG. 20, the rectangular deformed body 340 is arranged in the first fixed portion 341a arranged in the second quadrant, the second fixed portion 341b arranged in the first quadrant, and the fourth quadrant. It also has a third fixed portion 341c and a fourth fixed portion 341d arranged in the third quadrant. When the V-axis and W-axis that pass through the origin O and form 45 ° with respect to the X-axis and Y-axis are defined on the XY plane, the second and fourth fixed portions 341b and 341d are on the V-axis and the first The third fixed portions 341a and 341c are arranged symmetrically with respect to the origin O on the W axis, respectively. The first receiving portion 343a is arranged on the negative X-axis at an intermediate point between the first fixed portion 341a and the fourth fixed portion 341d. Further, the second receiving portion 343b is arranged on the positive Y axis at the intermediate point between the first fixing portion 341a and the second fixing portion 341b, and the third receiving portion 343c is the second fixing portion 341b. Is arranged on the positive X-axis at the intermediate point between the third fixed portion 341c and the third fixed portion 341c, and the fourth receiving portion 343d has a negative Y-axis at the intermediate point between the third fixed portion 341c and the fourth fixed portion 341d. It is placed on top.

The first deformed portion 345A is arranged between the first receiving portion 343a and the first fixed portion 341a in parallel with the Y axis, and the second deformed portion 345B is arranged between the first fixed portion 341a and the second receiving force. The third deformed portion 345C is arranged parallel to the X axis between the second receiving portion 343b and the second fixed portion 341b, and the third deformed portion 345C is arranged parallel to the X axis. The deformed portion 345D is arranged between the second fixed portion 341b and the third receiving portion 343c in parallel with the Y axis, and the fifth deformed portion 345E is formed between the third receiving portion 343c and the third fixed portion 341c. The sixth deformed portion 345F is arranged parallel to the Y axis between them, the sixth deformed portion 345F is arranged parallel to the X axis between the third fixed portion 341c and the fourth receiving portion 343d, and the seventh deformed portion 345G is arranged between them. It is arranged parallel to the X-axis between the 4th receiving portion 343d and the 4th fixed portion 341d, and the 8th deformed portion 345H is located between the 4th fixed portion 341d and the 1st receiving portion 343a. It is arranged parallel to. The specific structure of each of the deformed portions 345A to 345H has a curved structure similar to that of the deformed portions 45 to 48 of the first embodiment (see FIG. 21).

FIG. 22 is a schematic cross-sectional view showing the basic structure 301 of the force sensor according to the present embodiment, which employs the rectangular deformed body 340 of FIG. As shown in FIG. 22, the basic structure 301 is arranged on the negative side of the Z-axis with respect to the rectangular deformed body 340 described with reference to FIGS. 20 and 21 and the rectangular deformed body 340, and is an XYZ three-dimensional coordinate system. A fixed body 310 fixed to the rectangular deformed body 310 and a receiving body 320 arranged on the positive side of the Z axis with respect to the rectangular deformed body 340 and receiving a force and a moment acting on the rectangular deformed body 340. The fixed body 310 and the rectangular deformed body 340 are connected by four fixed portion side connecting members 331a to 331d in the four fixed portions 341a to 341d of the rectangular deformed body 340. That is, the first fixing portion side connecting member 331a connects the first fixing portion 341a of the rectangular deformed body 340 and the fixed body 310, and the second fixing portion side connecting member 331b is the second fixing portion of the rectangular deformed body 340. The 341b and the fixed body 310 are connected, and the third fixed portion side connecting member 331c connects the third fixed portion 341c of the rectangular deformed body 340 and the fixed body 310, and the fourth fixed portion side connecting member 331d. Connects the fourth fixed portion 341d of the rectangular deformed body 340 and the fixed body 310.

Further, the receiving body 320 and the rectangular deformed body 340 are connected by four receiving part side connecting members 332a to 332d in the four receiving parts 343a to 343d of the rectangular deformed body 340. That is, the first receiving portion side connecting member 332a connects the first receiving portion 343a of the rectangular deformed body 340 and the receiving body 320, and the second receiving portion side connecting member 332b is the rectangular deformed body 340. The second receiving portion 343b and the receiving body 320 are connected, and the third receiving portion side connecting member 332c connects the third receiving portion 343c of the rectangular deformed body 340 and the receiving body 320. The fourth receiving portion side connecting member 332d connects the fourth receiving portion 343d of the rectangular deformed body 340 and the receiving body 320. With the above configuration, the force and moment acting on the receiving body 320 are surely transmitted to the rectangular deformed body 340. In addition, in FIG. 22, only the cross-sectional view corresponding to FIG. 21 (a) is shown for the basic structure 301 of this embodiment, and the cross-sectional view corresponding to FIGS. 21 (c) to 21 (d) is shown. , Since it is substantially the same as FIG. 22, the illustration is omitted.

<4-2. Action of basic structure ＞
Next, the operation of the basic structure 301 will be described.

(4-2-1. When a force in the positive direction of the X axis + Fx acts)
FIG. 23 is a diagram for explaining the displacements that occur at the detection points A1 to A8 of the rectangular deformed body 340 shown in FIG. 20 when a force + Fx in the positive direction of the X axis acts on the receiving body 230. The meanings of symbols such as arrows in the figure are as explained in §1.

When the force + Fx in the positive direction of the X axis acts on the receiving portions 341a to 341d via the receiving body 320, the receiving portions 341a to 341d are displaced in the positive direction of the X axis. As a result, the third deformed portion 345C and the sixth deformed portion 345F are affected by the compressive force. In this case, the above-mentioned 1-2. As can be understood from the above, the third deformed portion 345C and the sixth deformed portion 345F are elastically deformed so that the radius of curvature of each curved portion 345Cp and 345Fp becomes smaller. Therefore, the detection points A3 and A6 are both displaced in the negative direction of the Z axis. On the other hand, as shown in FIG. 23, the second deformed portion 345B and the seventh deformed portion 345G are affected by the tensile force. In this case, the above-mentioned 1-2. As can be understood from the above, the second deformed portion 345B and the seventh deformed portion 345G are elastically deformed so that the radius of curvature of each curved portion 345Bp and 345Gp becomes large. Therefore, the detection points A2 and A7 are both displaced in the positive direction of the Z axis.

Further, the two receiving portions 343a and 343c located on the X-axis are orthogonal to the alignment direction (Y-axis direction) of the first, fourth, fifth, and eighth deformed portions 345A, 345D, 345E, and 345H. Move in the direction (X-axis direction). Therefore, in these four deformed portions 345A, 345D, 345E, and 345H, the corresponding detection points A1, A4, A5, and A8 are hardly displaced in the Z-axis direction.

The action of the basic structure 301 when the force + Fy in the positive direction of the Y axis acts on the receiving portions 341a to 341d of the basic structure 301 is the basic structure when the force + Fx in the positive direction of the X axis acts. The action of 301 may be considered by rotating it 90 ° counterclockwise around the origin O. Therefore, the detailed description thereof will be omitted here.

(4-2-2. When a force in the positive direction of the Z axis + Fz acts)
Next, FIG. 24 is a diagram for explaining the displacements that occur at the detection points A1 to A8 of the rectangular deformed body 340 shown in FIG. 20 when a force + Fz in the positive direction of the Z axis acts on the receiving body 320. is there. The meanings of symbols such as arrows in the figure are as explained in §1.

When a force + Fz in the Z-axis positive direction acts on the receiving portions 341a to 341d via the receiving body 320, each of the receiving portions 341a to 341d is displaced in the Z-axis positive direction. As a result, as shown in FIG. 24, the sides of the receiving portions 341a to 341d of the first to eighth deformed portions 345A to 345H are pulled in the positive direction of the Z axis. As a result, each of the detection points A1 to A8 is displaced in the positive direction of the Z axis.

(4-2-3. When the moment around the X-axis + Mx acts)
Next, FIG. 25 is a diagram for explaining the displacements that occur at the detection points A1 to A8 when the moment + Mx in the positive direction of the X axis acts on the rectangular deformed body 340 of FIG. The meanings of symbols such as arrows in the figure are as explained in §1.

When a moment + Mx around the X-axis forward acts on the receiving body 320, the second receiving portion 343b located on the positive Y-axis is displaced in the Z-axis positive direction (front direction in FIG. 25), and the negative Y-axis. The fourth receiving portion 343d located above is displaced in the negative direction of the Z axis (the depth direction in FIG. 25). Therefore, as shown in FIG. 33, the second and third deformed portions 345B and 345C are subjected to the action of the force in the positive direction of the Z axis in the same manner as when the force + Fz is applied. That is, 3-2-2. As described above, the second and third detection points A2 and A3 are displaced in the positive direction of the Z axis. On the other hand, as shown in FIG. 25, the sixth and seventh deformed portions 345F and 345G are subjected to the action of the force in the negative direction of the Z axis, contrary to the action of the force + Fz. In this case, the sixth and seventh detection points A6 and A7 are displaced in the negative direction of the Z axis.

Further, as shown in FIG. 25, the ends of the first receiving portion 343a and the third receiving portion 343c on the positive side of the Y axis are displaced in the positive direction of the Z axis (the front side in FIG. 25), and the negative Y axis is negative. The end on the side is displaced in the negative direction of the Z axis (the back side in FIG. 25). Along with these displacements, the first and fourth measurement sites A1 and A4 are displaced in the Z-axis positive direction, and the fifth and eighth measurement sites A5 and A8 are displaced in the Z-axis negative direction. However, as is clear from the distances from the X-axis, which is the central axis of rotation, to the measurement sites A1 to A8, the Z-axis directions generated in the first, fourth, fifth, and eighth measurement sites A1, A4, A5, and A8. The absolute value of the displacement of is smaller than the displacement in the Z-axis direction occurring at the second, third, sixth and seventh measurement sites A2, A3, A6 and A7.

The action of the basic structure 301 when the moment + My in the positive direction of the Y axis acts on the receiving portions 343a to 343d of the basic structure 301 originates from the case where the moment + Mx in the positive direction of the X axis acts. It may be considered by rotating 90 ° counterclockwise around O. Therefore, the detailed description thereof will be omitted here.

(4-2-4. When the moment around the Z axis + Mz acts)
Next, FIG. 26 is a diagram for explaining the displacement that occurs at each of the detection points A1 to A8 when the moment + Mz in the positive direction of the Z axis acts on the rectangular deformed body 340 of FIG. The meanings of symbols such as arrows in the figure are as explained in §2.

When a moment + Mz around the Z-axis is applied to the receiving body 320, as shown in FIG. 26, the first receiving portion 343a located on the negative X-axis is displaced in the negative direction of the X-axis, and the positive Y-axis is displaced. The upper second receiving portion 343b is displaced in the negative direction of the X axis, and the third receiving portion 343c located on the positive X axis is displaced in the positive direction of the Y axis and is located on the negative Y axis. The fourth receiving portion 343d is displaced in the positive direction of the X-axis. Therefore, as shown in FIG. 26, the second, fourth, sixth and eighth deformed portions 345B, 345D, 345F and 345H are affected by the compressive force. In this case, the above-mentioned 1-2. As can be understood from, the second, fourth, sixth and eighth deformed portions 345B, 345D, 345F and 345H are elastically deformed so that the radius of curvature of each curved portion 345Bp, 345Dp, 345Fp and 345Hp becomes smaller. .. Therefore, the detection points A2, A4, A6, and A8 are displaced in the negative direction of the Z axis.

On the other hand, as shown in FIG. 26, the first, third, fifth and seventh deformed portions 345A, 345C, 345E and 345G are affected by the tensile force. In this case, the above-mentioned 1-2. As can be understood from, the first, third, fifth and seventh deformed portions 345A, 345C, 345E, 345G are elastically deformed so that the radius of curvature of each curved portion 345Ap, 345Cp, 345Ep, 345Gp becomes large. .. Therefore, the detection points A1, A3, A5, and A7 are displaced in the positive direction of the Z axis.

As a summary of the above, FIG. 27 shows that when a force + Fx, + Fy, + Fz in each axial direction and a moment + Mx, + My, + Mz in each axial direction are applied to the receiving body 320 in the XYZ three-dimensional coordinate system, FIG. The increase / decrease in the separation distance between the detection points A1 to A8 of the rectangular deformed body 340 and the fixed body 310 is shown in a list. In FIG. 27, the reference numeral “+” written in the columns of the detection points A1 to A8 means that the separation distance between the detection point and the fixed body 310 increases, and the reference numeral “−” means that the separation distance decreases. "0" means that the separation distance does not change. Further, the symbols "++" and "−−" mean that the separation distance between the detection point and the fixed body 310 is further increased or decreased, respectively.

When the force and the moment acting on the receiving body 320 are in the negative direction and the negative rotation, the directions of the forces acting on the deformed portions 345A to 345H described above are reversed. Therefore, the increase / decrease in the separation distance between the detection points A1 to A8 and the fixed body 310 shown in the list in FIG. 27 are all reversed.

<4-3. Force sensor configuration ＞
Next, the configuration of the force sensor 301c having the basic structure 301 described in 4-1 and 4-2 will be described.

FIG. 28 is a schematic plan view showing the force sensor 301c according to the present embodiment using the basic structure 301 of FIG. 22, and FIG. 29 is a sectional view taken along line [29]-[29] of FIG. 28. .. In FIG. 28, for convenience of explanation, the drawing of the receiving body 320 is omitted.

As shown in FIGS. 28 and 29, the force sensor 301c acts on the basic structure 301 and the applied force based on the displacements generated at the detection points A1 to A8 of the deformed portions 345A to 315H of the basic structure 301. It has a detection circuit 350 for detecting a moment. As shown in FIGS. 28 and 29, the detection circuit 350 of the present embodiment includes a total of eight capacitive elements C1 to C8 arranged one at each detection point A1 to A8 of the deformed portions 345A to 315H. , It is connected to these capacitance elements C1 to C8, and has a measuring unit (not shown) for measuring the acting force based on the amount of fluctuation of the capacitance value of the capacitance elements C1 to C8.

The specific configuration of the eight capacitive elements C1 to C8 is the same as that of the first embodiment. That is, as shown in FIG. 29, in the basic structure 301, the second displacement electrode Em2 is provided at the second detection point A2, and the second fixed electrode Ef2 is placed on the fixed body 310 so as to face the second displacement electrode Em2. It is provided in. These electrodes Em2 and Ef2 constitute the second capacitance element C2. Similarly, in the basic structure 301, the third displacement electrode Em3 is provided at the third detection point A3, and the third fixed electrode Ef3 is provided on the fixed body 310 so as to face the third displacement electrode Em3. These electrodes Em3 and Ef3 constitute the third capacitance element C3.

Further, although not shown in detail, in the basic structure 301, the first and fourth to eighth displacement electrodes Em1 and Em4 to Em8 are provided at the first and fourth to eighth detection points A1 and A4 to A8, respectively. The first and fourth to eighth fixed electrodes Ef1 and Ef4 to Ef8 are provided on the fixed body 310 so as to face the displacement electrodes Em1 and Em4 to Em8. The displacement electrodes Em1, Em4 to Em8 and the fixed electrodes Ef1, Ef4 to Ef8 facing each other constitute the first and fourth to eighth capacitive elements C1 and C4 to C8.

Specifically, as shown in FIG. 29, the displacement electrodes Em1 to Em8 are placed on the lower surfaces of the first to eighth deformed body side supports 361 to 368 supported by the corresponding measurement sites A1 to A8, from the first to the first. It is supported via the eighth displacement substrate Im1 to Im8. Further, the fixed electrodes Ef1 to Ef8 are supported on the upper surfaces of the first to eighth fixed body side supports 371 to 378 fixed to the upper surface of the fixed body 310 via the first to eighth fixed substrates If1 to If8. ing. The displacement electrodes Em1 to Em8 all have the same area, and the fixed electrodes Ef1 to Ef8 also have the same area. However, as in the first embodiment, the electrode area of the displacement electrodes Em1 to Em8 is larger than the electrode area of the fixed electrodes Ef1 to Ef8. In the initial state, the effective facing areas and separation distances of the electrodes of each set constituting the capacitive elements C1 to C8 are all the same.

Further, as shown in FIGS. 28 and 29, the force sensor 301c is an electric signal indicating the force and moment acting on the receiving body 320 based on the elastic deformation generated in each of the deformed portions 345A to 345H of the deformed body 340. It has a detection circuit 350 that outputs. In FIGS. 28 and 29, the wiring for electrically connecting the capacitance elements C1 to C8 and the detection circuit 350 is not shown.

When the fixed body 310, the receiving body 320, and the deformed body 340 are made of a conductive material such as metal, the first to eighth displacement substrates Im1 to Im8 and the first to first ones are prevented so that the electrodes are not short-circuited. 8 The fixed substrates If1 to If8 need to be made of an insulator. This point is the same as that of the first embodiment.

<4-4. Action of force sensor ＞
Next, when the forces Fx, Fy, Fz in each axial direction and the moments Mx, My, Mz around each axis act on the above force sensor 301c in the XYZ three-dimensional coordinate system, the force sensor 301c The action of is described.

(4-4-1. When a force in the positive direction of the X axis + Fx acts)
First, when a force + Fx in the positive direction of the X axis acts on the force sensor 301c, as can be seen from the column of + Fx in FIG. 27, in the second and seventh capacitance elements C2 and C7, the separation distance between the electrodes is both. As it increases, the capacitance value decreases. On the other hand, in the third and sixth capacitance elements C3 and C6, the separation distance between the electrodes is reduced together, so that the capacitance value is increased. In the remaining first, fourth, fifth and eighth capacitance elements C1, C4, C5 and C8, the capacitance value does not change because the separation distance between the electrodes does not substantially change. When a force −Fx in the negative direction of the X axis acts on the force sensor 301c, the increase / decrease of the capacitance values of the second, third, sixth and seventh capacitance elements C2, C3, C6 and C7 are reversed. ..

(4-4-2. When a force in the positive direction of the Y axis + Fy acts)
Next, when a force + Fy in the positive direction of the Y axis acts on the force sensor 301c, as can be understood from the column of + Fy in FIG. 27, in the fifth and eighth capacitance elements C5 and C8, the separation distance between the electrodes is increased. Since both increase, the capacitance value decreases. On the other hand, in the first and fourth capacitance elements C1 and C4, the separation distance between the electrodes is reduced together, so that the capacitance value is increased. In the remaining second, third, sixth and seventh capacitance elements C2, C3, C6 and C7, the capacitance value does not change because the separation distance between the electrodes does not substantially change. When a force −Fy in the negative direction of the Y axis acts on the force sensor 301c, the increase and decrease of the capacitance values of the first, fourth, fifth and eighth capacitance elements C1, C4, C5 and C8 are reversed. ..

(4-4-3. When a force in the positive direction of the Z axis + Fz acts)
Next, when a force + Fz in the positive direction of the Z axis acts on the force sensor 301c, as can be seen from the column of + Fz in FIG. 27, the separation distance between the electrodes increases in all the capacitive elements C1 to C8. , The capacitance value decreases. When a force −Fz in the negative Z-axis direction acts on the force sensor 301c, the distance between the electrodes in all the capacitance elements C1 to C8 decreases, so that the capacitance value increases.

(4-4-4. When the moment around the X-axis + Mx acts)
Next, when a moment + Mx around the X-axis is applied to the force sensor 301c, as can be understood from the column of + Mx in FIG. 27, in the first to fourth capacitance elements C1 to C4, the separation distance between the electrodes is increased. As it increases, the capacitance value decreases. However, due to the difference in the amount of change in the separation distance between the electrodes, the capacitance value is significantly reduced in the second and third capacitance elements C2 and C3 than in the first and fourth capacitance elements C1 and C4. On the other hand, in the fifth to eighth capacitance elements C5 to C8, the capacitance value increases because the separation distance between the electrodes decreases. However, due to the difference in the amount of change in the separation distance between the electrodes, the capacitance value increases more in the sixth and seventh capacitance elements C6 and C7 than in the fifth and eighth capacitance elements C5 and C8. When a moment −Mx around the negative axis of the X axis acts on the force sensor 301c, the increase / decrease in the capacitance value of each of the capacitance elements C1 to C8 is reversed.

(4-4-5. When the moment around the Y-axis + My acts)
Next, when a moment + My in the positive direction of the Y axis acts on the force sensor 301c, as can be understood from the column of + My in FIG. 27, the first, second, seventh and eighth capacitive elements C1, C2, C7 , C8, the capacitance value decreases because the separation distance between the electrodes increases. However, due to the difference in the amount of change in the separation distance between the electrodes, the capacitance value is significantly reduced in the first and eighth capacitance elements C1 and C8 than in the second and seventh capacitance elements C2 and C7. On the other hand, in the third to sixth capacitance elements C3 to C6, the capacitance value increases because the separation distance between the electrodes decreases. However, due to the difference in the amount of change in the separation distance between the electrodes, the capacitance value increases more significantly in the fourth and fifth capacitance elements C4 and C5 than in the third and sixth capacitance elements C3 and C6. When a moment −My around the negative axis of the Y axis acts on the force sensor 301c, the increase / decrease in the capacitance value of each of the capacitance elements C1 to C8 is reversed.

(4-4-6. When the moment around the Z-axis + Mz acts)
Next, when a moment + Mz around the Z-axis forward acts on the force sensor 301c, as can be understood from the column of + Mz in FIG. 27, the first, third, fifth and seventh capacitive elements C1, C3, C5 , C7, the capacitance value decreases because the separation distance between the electrodes increases. On the other hand, in the second, fourth, sixth and eighth capacitance elements C2, C4, C6 and C8, the capacitance value increases because the separation distance between the electrodes decreases. When a moment −Mz around the negative axis of the Z axis acts on the force sensor 301c, the increase / decrease in the capacitance value of each of the capacitance elements C1 to C8 is reversed.

The increase / decrease in the capacitance value of each of the capacitance elements C1 to C8 described above is summarized in FIG. 30. In FIG. 30, the symbol “+” means that the capacitance value increases, and the symbol “−” means that the capacitance value decreases. Further, the symbol "++" means that the capacitance value is greatly increased, and the symbol "−−" means that the capacitance value is greatly decreased. On the other hand, the number "0" means that the capacitance value does not change substantially.

(4-4-7. Calculation method of applied force and moment)
In view of the fluctuation of the capacitance value of the capacitance elements C1 to C8 as described above, the detection circuit 350 uses the following [Equation 2] to act on the force sensor 301c to act on the force Fx, Fy, Fz and the moment Mx. Calculate My and Mz. In [Equation 2], C1 to C8 indicate the amount of fluctuation in the capacitance value of the first to eighth capacitance elements C1 to C8.
[Equation 2]
Fx = -C2 + C3 + C6-C7
Fy = C1 + C4-C5-C8
Fz = -C1-C2-C3-C4-C5-C6-C7-C8
Mx = -C1-C2-C3-C4 + C5 + C6 + C7 + C8
My = -C1-C2 + C3 + C4 + C5 + C6-C7-C8
Mz = -C1 + C2-C3 + C4-C5 + C6-C7 + C8

When the force and moment acting on the force sensor 301c are in the negative direction, Fx, Fy, Fz, Mx, My and Mz on the left side are set to -Fx, -Fy, -Fz, -Mx, -My and It may be set to -Mz. However, in this case, since the signs of C1 to C4 on the right side are also reversed, the force and moment acted by [Equation 2] are measured regardless of the sign of the acting force and moment.

However, according to [Equation 2], the force Fz in the Z-axis direction is obtained by the sum of −C1 to −C8. Therefore, it should be noted that the force Fz is easily affected by temperature changes and in-phase noise in the usage environment of the force sensor 301c.

<4-5. Other axis sensitivity of force sensor ＞
Next, with reference to FIG. 31, the sensitivity of the force sensor 301c according to the present embodiment will be described. FIG. 31 is a chart showing a list of the forces Fx, Fy, Fz in each axial direction and the other axis sensitivities VFx to VMz of the moments Mx, My, and Mz around each axis in the force sensor 301c shown in FIG. 28.

The numbers arranged in the chart of FIG. 31 are such that the capacitive element with the symbol “+” is +1 for each force Fx, Fy, Fz and each moment Mx, My, Mz in the chart shown in FIG. It is a value obtained by substituting the capacitive element with the symbol "-" as -1 and substituting it on the right side of each of the above-mentioned [Equation 2]. That is, the number "8" written in the square where the row VFx and the column Fx intersect is based on the row of Fx in FIG. 30 in the formula indicating Fx (the first formula of [Equation 2]). It is a value obtained by substituting C7 = -1 and C3 = C6 = + 1. Further, the number "0" written in the square where the row VFx and the column Fy intersect is C1 = C4 = + 1 and C5 = C8 = based on the row of Fy in FIG. 30 in the formula indicating Fx. It is a value obtained by substituting -1. The same applies to the numbers in other squares.

When there is no other-axis sensitivity, all the squares other than the six squares located on the diagonal line from the upper left to the lower right in the chart of FIG. 31 become zero. However, as shown in FIG. 31, for example, since Fx has other axis sensitivities of My, Fx and My influence each other. Therefore, it is not possible to detect an accurate force and moment as it is. However, in this case, the inverse matrix of the actual matrix of other-axis sensitivity (the matrix of 6 rows and 6 columns corresponding to the chart of FIG. 31) is obtained, and this inverse matrix is multiplied by the output of the force sensor 301c by a correction calculation. The sensitivity of the other axis can be set to zero.

According to the force sensor 301c according to the present embodiment as described above, the fixed portion side curved portion 345Af is provided between the main curved portions 345Ap to 345Hp and the fixed portions 341a to 341d and the receiving portions 343a to 343d adjacent thereto. By interposing ~ 345Hf and the receiving portion side bending portions 345Am to 345Hm, respectively, stress concentration is avoided at the connection portion between the main bending portion 345Ap to 345Hp and the adjacent 341a to 341d and the receiving portion 343a to 343d. can do. Therefore, according to the present embodiment, it is possible to provide the capacitance type force sensor 301c having high reliability.

Further, the force sensor 301c according to the present embodiment can measure all six components of the forces Fx, Fy, Fz in each axial direction of the XYZ three-dimensional coordinate system and the moments Mx, My, Mz around each axis. it can. Further, the force sensor 301c can detect five components excluding the force Fz in the Z-axis direction by the difference between the capacitance values of the eight capacitance elements C1 to C8. That is, according to the present embodiment, when measuring the five components Fx, Fy, Mx, My, and Mz excluding the force Fz, a force sensor 301c that is not easily affected by temperature changes in the usage environment and in-phase noise is provided. can do.

Further, since the deformed body has a rectangular deformed body 340 having a square shape symmetrical with respect to the X-axis and the Y-axis, the rectangular deformed body 340 is symmetrically deformed due to the applied force and moment. To do. Therefore, it is easy to measure the force and the moment acting based on the deformation.

In particular, the rectangular variant 340 is positioned on the XY plane so that its center coincides with the origin O of the XYZ three-dimensional coordinate system. Then, four receiving portions 343a to 343d are arranged one by one at the midpoint of each side of the rectangular deformed body 340, and four fixed portions are arranged one by one at each vertex of the rectangular deformed body 340. .. With such a symmetrical configuration, the capacitance elements C1 to C8 are arranged symmetrically with respect to the X-axis and the Y-axis, so that it is extremely easy based on the fluctuation amount of the capacitance value of each capacitance element C1 to C8. The acting force and moment can be measured.

Further, the main curved surfaces 345Apa to 345Hpa of the main curved portions 345Ap to 345Hp are composed of curved surfaces along an arc when observed along a closed loop rectangular path of the rectangular deformed body 340. Therefore, the elastic deformation generated in the main curved portion 345Ap to 345Hp due to the force and the moment acting on the force sensor 301c can be further stabilized.

<<< §5. Force sensor according to the fourth embodiment of the present invention >>>
Next, the force sensor according to the fourth embodiment of the present invention will be described in detail.

<5-1. Structure of basic structure ＞
FIG. 32 is a schematic front view showing a basic structure 401 adopted in the force sensor according to the fourth embodiment of the present invention. Unlike the third embodiment described above, the basic structure 401 of the present embodiment has a donut-shaped annular variant 440. The annular plasmodium 440 is a structure in which both the inner peripheral contour and the outer peripheral contour form a circle, and is arranged on the XY plane with the origin O as the center when viewed from the Z-axis direction. The annular plasmodium 440 alternates with four fixed portions 441a-441d fixed to the XYZ three-dimensional coordinate system along a circular closed-loop path and fixed portions 441a-441d in the closed-loop path. The four receiving portions 443a to 443d, which are positioned and affected by the force and the moment, are positioned one by one between the fixed portions 441a to 441d and the receiving portions 443a to 443d, which are adjacent to each other in the closed loop path. It has a total of eight deformed portions 445A to 445H.

As shown in FIG. 32, when the V-axis and the W-axis that pass through the origin O and form 45 ° with respect to the X-axis and the Y-axis are defined on the XY plane, the four fixed portions 441a to 441d are on the V-axis and W. They are arranged one by one on the axis. Further, four receiving portions 443a to 443d are arranged one by one on the X-axis and one on the Y-axis. The distances from the origin O to the fixed portions 441a to 441d and the receiving portions 443a to 443d are all equal. As shown in FIG. 32, the eight deformed portions 445A to 445H have a deformed portion located in the region sandwiched between the negative X-axis and the positive W-axis as the first deformed portion 445A, and are circles of the annular deformed body 440. It will be referred to as a second deformed portion 445B, a third deformed portion 445C, ..., And an eighth deformed portion 445H in a clockwise direction along the annular path. The specific structure of each of the deformed portions 445A to 445H has a curved structure similar to that of the deformed portions 45 to 48 of the first embodiment (see FIG. 21). In short, the annular deformed body 440 of the present embodiment is formed by bending each side of the rectangular deformed body 340 (see FIG. 20) of the third embodiment to form an annular shape. Therefore, the basic structure 401 according to the present embodiment is different from the third embodiment in that such an annular variant is adopted.

Further, with the adoption of the annular plasmodium 440, the fixed body 410 and the receiving body 420 are also configured so that the outer peripheral contour line is a circle centered on the origin O. However, in FIG. 21, for convenience of explanation, the drawing of the receiving body 420 is omitted. On the other hand, since the other configurations are the same as those of the third embodiment, the same reference numerals are given to the configurations common to those of the third embodiment in FIG. 32, and detailed description thereof will be omitted.

<5-2. Action of basic structure ＞
Next, the operation of the basic structure 401 will be described. As described above, the annular deformed body 440 can be regarded as being configured by bending each side of the rectangular deformed body 340 according to the third embodiment. Therefore, when the forces Fx, Fy, Fz in each axial direction of the XYZ three-dimensional coordinate system and the moments Mx, My, Mz around each axis act on the receiving portions 443a to 443d of the annular deformed body 440, each deformed portion. The increase / decrease in the separation distance between the measurement sites A1 to A8 of the 445A to 445H and the fixed body 410 is essentially the same as the increase / decrease in the separation distance in the third embodiment.

However, when the shape of the deformed body is changed from rectangular to circular and a force + Fx in the positive direction of the X axis acts on the receiving portions 443a to 443d via the receiving body 420, the first, fourth, and so on. Elastic deformation is observed at the curved portions 445Ap, 445Dp, 445Ep, and 445Hp of the fifth and eighth deformed portions 445A, 445D, 445E, and 445H. Specifically, since the first and eighth deformed portions 445A and 445H are slightly compressed and deformed, the corresponding first and eighth measurement sites A1 and A8 are displaced in the negative direction of the Z axis. On the other hand, since the 4th and 5th deformation portions 445D and 445E are slightly tensilely deformed, the corresponding 4th and 5th measurement sites A4 and A5 are displaced in the Z-axis positive direction. Similarly, when a force + Fy in the positive direction of the Y axis acts on the receiving portions 443a to 443d via the receiving body 420, the sixth and seventh deformed portions 445F and 445G are slightly compressed and deformed. The 6th and 7th measurement sites A6 and A7 are displaced in the negative direction of the Z axis. On the other hand, since the second and third deformation portions 445B and 445C are slightly tensilely deformed, the corresponding second and third measurement sites A2 and A3 are displaced in the Z-axis positive direction. When other forces Fz and moments Mx, My, and Mz act, the displacement in the Z-axis direction that occurs in each of the measurement sites A1 to A8 is the same as in the third embodiment.

When the forces Fx, Fy, Fz in each axial direction of XYZ and the moments Mx, My, Mz around each axis act on the receiving body 420 of the basic structure 401 according to the present embodiment, the measurement sites A1 to A8 The increase / decrease in the separation distance from the fixed body 410 is shown in a list in FIG. 33. In FIG. 33, the symbol “+” means that the separation distance between the measurement sites A1 to A8 and the fixed body 410 increases, and the symbol “−” means that the separation distance decreases. Further, the symbol "++" means that the separation distance is greatly increased, and the symbol "−−" means that the separation distance is greatly decreased. Further, the symbols “(+)” and “(−)” in parentheses mean that the degree of increase / decrease in the separation distance between the measurement sites A1 to A8 and the fixed body 410 is slight.

<5-3. Force sensor configuration ＞
Next, the configuration of the force sensor 401c having the basic structure 401 described in 5-1 and 5-2 will be described.

FIG. 34 is a schematic plan view showing the force sensor 301c according to the present embodiment using the basic structure 301 of FIG. 32. As shown in FIG. 34, the force sensor 401c detects the applied force and moment based on the displacements generated at the above-mentioned basic structure 401 and the displacements A1 to A8 of the deformed portions 445A to 415H of the basic structure 401. It has a detection circuit 450 and the like. As shown in FIG. 34, the detection circuit 450 of the present embodiment includes a total of eight capacitive elements C1 to C8 arranged one at each detection point A1 to A8 of the deformed portions 445A to 445H, and these. It is connected to the capacitance elements C1 to C8, and has a measuring unit (not shown) that measures the applied force based on the amount of fluctuation in the capacitance value of the capacitance elements C1 to C8. In FIG. 34, the wiring for electrically connecting the capacitance elements C1 to C8 and the detection circuit 450 is not shown. The configuration of each capacitive element, the mounting mode to the basic structure 401, and other configurations are substantially the same as those of the third embodiment. Therefore, in FIG. 34, substantially the same reference numerals are given to the same components as those in the third embodiment, and detailed description thereof will be omitted.

<5-4. Action of force sensor ＞
As can be understood from the above description, the force sensor 401c behaves substantially the same as the force sensor 301c according to the third embodiment with respect to the acting force and moment. In particular, when the four components of the forces Fz in the Z-axis direction and the moments Mx, My, and Mz around each axis of XYZ act on the force sensor 401c, the capacitance values of the capacitance elements C1 to C8 are obtained. The variation of is the same as that of the force sensor 301c according to the third embodiment.

On the other hand, when the forces Fx and Fy in the X and Y axis directions act due to the difference in the shape of the deformed body, the fluctuation of the capacitance value of each of the capacitance elements C1 to C8 is the third embodiment. It is slightly different from the force sensor 301c. For example, when a force + Fx in the positive direction of the X-axis acts on the receiving body 420, the receiving portions 443a to 443d of the annular deformed body 440 are displaced in the positive direction of the X-axis. At this time, the first receiving portion 443a is displaced toward the center (origin O) of the annular deformed body 440, so that the first and eighth deformed portions 445A and 445H are slightly displaced in the radial direction of the annular deformed body 440. It is compressed. As a result, the first and eighth main bending portions 445Ap and 445Hp are elastically deformed so that the radius of curvature becomes slightly smaller, and the corresponding detection points A1 and A8 are slightly displaced in the negative direction of the Z axis. Similarly, as the third receiving portion 443c is displaced away from the center (origin O) of the annular deformed body 440, the fourth and fifth deformed portions 445D and 445E are slightly displaced in the circumferential direction of the annular deformed body 440. Pulled by. As a result, the fourth and fifth main bending portions 445Dp and 445Ep are elastically deformed so that the radius of curvature is slightly larger, and the corresponding detection points A4 and A5 are slightly displaced in the positive direction of the Z axis.

On the other hand, the elastic deformations that occur in the remaining second, third, sixth and seventh deformation parts 445B, 445C, 445F and 445G, and the displacements of the corresponding measurement parts A2, A3, A6 and A7 are the third implementation. It is similar to the form of. Of course, the absolute value of the displacement of these measurement sites A2, A3, A6, and A7 is larger than the absolute value of the displacement of the measurement sites A1, A4, A5, and A8 described above. When a force in the negative direction of the X-axis acts on the receiving body 420 of the force sensor 401c, the directions of the forces acting on the deformed portions 445A to 445H are opposite, so that the detection points A1 to A8 have different directions. The direction of displacement is also reversed.

When the force Fy in the Y-axis direction acts on the receiving body 420 of the force sensor 401c, the case where the above-mentioned force Fx in the X-axis direction acts is rotated 90 ° counterclockwise around the origin O. Just think about it. Therefore, in the force sensor 401c, when the force Fy in the Y-axis direction acts on the receiving body 320 of the force sensor 301c according to the third embodiment, the second, third, and third forces are not displaced. A slight displacement in the Z-axis direction is also detected at the 6th and 7th measurement sites A2, A3, A6, and A7.

From the above, in the force sensor 401c according to the present embodiment, when the forces Fx, Fy, Fz in each axial direction and the moments Mx, My, Mz around each axis act in the XYZ three-dimensional coordinate system, each detection point. It can be seen that the capacitance values of the capacitance elements C1 to C8 associated with A1 to A8 vary substantially in the same manner as in the third embodiment. However, in the present embodiment, when the force Fx in the X-axis direction is applied, the measurement sites A1, A4, A5, and A8 are slightly displaced in the Z-axis direction, and the capacitance elements C1, C4 are accompanied by this. , C5 and C8 have slightly fluctuating capacitance values. Similarly, when a force Fy in the Y-axis direction is applied, a slight displacement in the Z-axis direction occurs in the measurement sites A2, A3, A6, and A7, and the capacitance elements C2, C3, C6, and C7 are accompanied by this. The capacitance value fluctuates slightly.

The increase / decrease in the capacitance value of each of the capacitance elements C1 to C8 described above is summarized in FIG. 35. In FIG. 35, the symbol “+” means that the capacitance value increases, and the symbol “−” means that the capacitance value decreases. Further, the symbol "++" means that the capacitance value is greatly increased, and the symbol "−−" means that the capacitance value is greatly decreased. Further, the parenthesized symbols "(+)" and "(-)" mean that the capacitance value fluctuates slightly.

<5-5. Calculation method of applied force and moment ＞
In view of the fluctuation of the capacitance value of the capacitance elements C1 to C8 as described above, the detection circuit 450 uses the following [Equation 3] to act on the force sensor 401c to perform the forces Fx, Fy, Fz and the moment Mx. Calculate My and Mz. In [Equation 3], C1 to C8 indicate the amount of fluctuation in the capacitance value of the first to eighth capacitance elements C1 to C8.
[Equation 3]
Fx = -C2 + C3 + C6-C7
Fy = C1 + C4-C5-C8
Fz = -C1-C2-C3-C4-C5-C6-C7-C8
Mx = -C1-C2-C3-C4 + C5 + C6 + C7 + C8
My = -C1-C2 + C3 + C4 + C5 + C6-C7-C8
Mz = -C1 + C2-C3 + C4-C5 + C6-C7 + C8

Alternatively, the detection circuit 450 uses only the capacitive elements marked with “++” and “−−” in FIG. 35 for Mx and My, and the force acting by using the following [Equation 4]. Fx, Fy, Fz and moments Mx, My, Mz may be calculated. Of course, this also applies to the third embodiment.
[Equation 4]
Fx = -C2 + C3 + C6-C7
Fy = C1 + C4-C5-C8
Fz = -C1-C2-C3-C4-C5-C6-C7-C8
Mx = -C2-C3 + C6 + C7
My = -C1-C2 + C3 + C4 + C5 + C6-C7-C8
Mz = -C1 + C2-C3 + C4-C5 + C6-C7 + C8

This [Equation 3] is the same as [Equation 2] described in the third embodiment. As described above, in the force sensor 401c, when the forces Fx and Fy in the X and Y axis directions are applied, the capacitance value fluctuates slightly as indicated by the parentheses in FIG. 35. Exists. However, the fluctuation amount of these capacitance values is extremely small as compared with the fluctuation amount of the capacitance value of the capacitance element shown by the reference numerals without parentheses. Therefore, when calculating the acting force and moment, the change in the capacitance value of the capacitive element indicated by the code in parentheses may be treated as substantially zero.

When the force and moment acting on the force sensor 401c are in the negative direction, Fx, Fy, Fz, Mx, My and Mz on the left side are set to -Fx, -Fy, -Fz, -Mx, -My and -Mz. It should be. Since the force Fz in the Z-axis direction is obtained by the sum of -C1 to -C8, it should be noted that the force Fz is easily affected by temperature changes and in-phase noise in the usage environment of the force sensor 301c. is there. Further, the same method as that of the third embodiment can be adopted for the correction calculation for canceling the sensitivity of the other axis. As a result, the influence of the sensitivity of the other axis can be made substantially zero, and the high-precision force sensor 401c can be achieved.

The force sensor 401c according to the present embodiment as described above can also obtain the same action and effect as the force sensor 301c according to the third embodiment.

<5-6. Specific method of correction calculation ＞
Here, the method of correction calculation will be described in detail. FIG. 36 shows that when the forces Fx, Fy, Fz in the axial directions of the XYZ three-dimensional coordinate system and the moments Mx, My, Mz in the axial directions act on the receiving body 420, the capacitance elements C1 to C8 are generated. It is a chart which shows the fluctuation of a capacitance value. Further, FIG. 37 is a chart showing a list of other axis sensitivities of the force sensor 401c of FIG. 34 calculated based on the fluctuation of each capacitance value shown in FIG. 36.

When the forces Fx, Fy, Fz in each axial direction and the moments Mx, My, Mz in each axial direction act on the receiving body 420, the capacitance values of the capacitive elements C1 to C8 are shown in FIG. It fluctuates as shown in 36. It should be noted that the chart of FIG. 36 and the chart of FIG. 35 differ in the reference numerals of the columns corresponding to (+) and (−) in FIG. 35. The reason for this is that FIG. 35 shows the displacement at points A1 to A8 in FIG. 34, FIG. 36 shows the actual change in the capacitance value of the capacitance element in FIG. 34, and FIG. 36 shows the actual change in the capacitance value, and FIG. 36 shows the finite element analysis. It is an analysis result, and it is conceivable that a calculation error may occur due to the mesh setting at the time of analysis. In any case, since the correction calculation is performed when measuring the applied force and moment, the above-mentioned difference in sign is not a big problem.

When the other axis sensitivity of the force sensor 401c according to the present embodiment is evaluated based on each numerical value shown in FIG. 36, it is as shown in FIG. 37. The sensitivity of the other axis in FIG. 37 is calculated based on the above-mentioned [Equation 4]. Specifically, the numerical value of 0.88 described in the square where the row Fx and the column VFx of FIG. 37 intersect is expressed in the first equation of [Equation 4] of Fx = -C2 + C3 + C6-C7, in FIG. 36. It is a numerical value obtained by substituting C2 = −0.22, C3 = C6 = 0.22 and C7 = −0.22 described in the line of Fx. Similarly, for example, the numerical value 2.00 described in the square where the row My and the column VFx intersect can be found in the first equation of [Equation 4] of Fx = -C2 + C3 + C6-C7 in the row of My in FIG. It is a numerical value obtained by substituting C2 = −0.50, C3 = C6 = 0.50 and C7 = −0.50 described. Numerical values are calculated in the same way for other squares.

The chart of FIG. 37 created as described above can be regarded as a 6-by-6 matrix. This inverse matrix is shown in FIG. By multiplying this inverse matrix by the output from the detection circuit 450 of the force sensor 401c, the sensitivity of the other axis can be canceled.

In each of the above force sensors, the deformed body 40 shown in FIG. 4 is operated. However, it is also possible to adopt a modified body having a configuration different from that of FIG. 39 and 40 are schematic side views showing a part of the deformed bodies 540A and 540B according to the modified example of FIG. Specifically, in FIGS. 39 and 40, only the portion of the deformed bodies 540A and 540B corresponding to FIG. 4 is shown.

In the example shown in FIG. 39, the fixed portion side straight portion in which the surface on the positive side of the Z axis and the surface on the negative side of the Z axis are parallel planes between the main curved portion 546Ap and the fixed portion side curved portion 546Af. 546 Afs is provided. Further, between the main curved portion 546Ap and the receiving portion side curved portion 546Am, a receiving portion side straight portion 546Ams in which the surface on the positive side of the Z axis and the surface on the negative side of the Z axis are parallel to each other is provided. Has been done. Further, the surface of the deformed portion 546A on the positive side of the Z axis has a curvature different from the example shown in FIG. That is, the surface 546pb on the Z-axis positive side of the main curved portion 546Ap is a curved surface along an arc having a radius r1 centered on the point O1 as in FIG. 4, but as shown in FIG. 39, the fixed portion side. The surface 546fb on the Z-axis positive side of the curved portion 546Af is a curved surface along an arc having a radius r5 centered on the point O5, and is curved toward the Z-axis positive side. Further, as shown in FIG. 39, the surface 546 mb on the Z-axis positive side of the receiving portion-side curved portion 546 Am is a curved surface along an arc having a radius r7 centered on the point O7, and faces the Z-axis positive side. Is curved.

Further, the main curved surface 546pa of the main curved portion 546Ap is a curved surface along an arc having a radius r2 centered on the point O2 as in FIG. 4, but as shown in FIG. 39, the curved surface on the fixed portion side 546fa Is a curved surface along an arc having a radius r6 centered on the point O6, and is curved in the positive direction of the Z axis. Further, as shown in FIG. 39, the receiving portion side curved surface 546ma is a curved surface along an arc having a radius r8 centered on the point O8, and is curved in the positive direction of the Z axis. Although not shown, the above is the same for the remaining deformed portions 545A, 547A, and 548D.

That is, the surface of the deformed body 540A shown in FIG. 39 on the negative side of the Z axis is deformed as shown in FIG. 4 except that the fixed portion side straight portions 545 Afs to 548 Afs and the receiving portion side straight portions 545 Ams to 548 Ams are provided. It has the same structure as the body 40. In the illustrated example, the points O5 and O6 are arranged on a straight line parallel to the Z axis, the points O7 and O8 are arranged on a straight line parallel to the Z axis, and further, r5 = r6 = r7 = r8. It has become. In this case, since each of the deformed portions 565A to 568A is symmetrically configured with respect to the corresponding measurement sites A1 to A4, the acting force or moment can be easily calculated.

The main curved portion 545Ap to 548Ap and the fixed portion side curved portion 545Af to 548Af may be directly connected without passing through the fixed portion side straight portion 545Afs to 548Afs. Further, the main curved portion 545Ap to 548Ap and the receiving portion side curved portion 545Am to 548Am may be directly connected without passing through the receiving portion side straight portion 545Ams to 548Ams. An example of this is shown in FIG. In FIG. 40, the components corresponding to FIG. 39 are designated by the same reference numerals as those in FIG. 39, and detailed description thereof will be omitted here.

The force sensor using the deformed bodies 540A and 540B shown in FIGS. 39 and 40 can also provide the same operation as the force sensor 1c using the deformed body 40 shown in FIG.

In each force sensor of §1 to §5, 4 or 8 capacitive elements are arranged, but 5 to 7 or 9 or more capacitive elements may be arranged. Also in this case, by outputting the electric signals T1 to T3 according to each case, the same operation as that of the above-described force sensor can be provided. Further, in each of the force sensors of §1 to §5, the fixed portion and the receiving portion are all adjacent to each other, but the present invention is not limited to such a mode. That is, some receiving portions may be adjacent to each other, or some fixed portions may be adjacent to each other. However, in this case, it is necessary that at least one pair of a receiving portion and a fixed portion adjacent to each other is provided.

<<< §6. Modification example >>>

<Modification example 1>
In each of the above force sensors, the main curved portion curved toward the negative side of the Z axis, and the curved surface on the fixed portion side and the curved surface on the receiving portion side curved toward the positive side of the Z axis are the Z of the deformed body. It was provided on the negative side of the shaft. However, it is not limited to such an embodiment. For example, on the Z-axis positive side surface of the deformed body, a main curved portion curved toward the Z-axis positive side, a fixed portion-side curved surface curved toward the Z-axis negative side, and a receiving portion-side curved surface. May be provided. In this case, the measurement sites A1 to A4 or A1 to A8 of each deformed body are defined on the Z-axis positive side of each main curved portion.

Alternatively, the deformed portion of the deformed body may be curved in the radial direction instead of the Z-axis direction. That is, in the deformed body 40 shown in FIG. 1, each of the deformed portions 45 to 48 is mainly curved inward (inward in the radial direction) or outward (outward in the radial direction) with respect to the closed loop-shaped (annular) path. It may have a main curved portion having a curved surface. Then, a fixed portion side curved portion having a fixed portion side curved surface that connects these main curved portions and the fixed portions 41 and 42 and is curved inward or outward with respect to the closed loop-shaped path, and a main curved portion. And the receiving portions 43 and 44 may be connected to each other, and may have a receiving portion side curved portion having a receiving portion side curved surface curved inward or outward with respect to a closed loop-shaped path.

Specifically, when the main curved portion is curved outward in the radial direction, the main curved surface, the fixed portion side curved surface, and the receiving portion side curved surface are defined as the outer peripheral surface of the deformed body. To. At this time, the curved surface on the fixed portion side and the curved surface on the receiving portion side may be curved inward in the radial direction with respect to the closed loop path. In this case, the measurement sites A1 to A4 or A1 to A8 of each deformed body are defined on the outer peripheral surface of the deformed body (the radial outer surface of the main curved portion). Alternatively, when the main curved portion is curved inward in the radial direction, the main curved surface, the fixed portion side curved surface, and the receiving portion side curved surface are defined as the inner peripheral surface of the deformed body. At this time, the curved surface on the fixed portion side and the curved surface on the receiving portion side may be curved outward in the radial direction with respect to the closed loop path. In this case, the measurement sites A1 to A4 or A1 to A8 of each deformed body are defined on the inner peripheral surface (inward surface in the radial direction) of the deformed body.

<Modification example 2>
Next, a modified example in which the fixed body 10 and the receiving body 20 shown in FIG. 1 are modified will be described with reference to FIGS. 48 and 49. FIG. 48 is a schematic plan view showing a modified example of the basic structure 1 of FIG. 1, and FIG. 49 is a cross-sectional view taken along the line [48]-[48] of FIG.

In the example shown in FIG. 1, the deformed body 40 is arranged so as to be sandwiched between the fixed body 10 and the receiving body 20. On the other hand, in the examples shown in FIGS. 48 and 49, the fixed body 10a and the receiving body 20a are arranged on the same side with respect to the deformed body 40. Specifically, as shown in FIG. 49, the two fixed bodies 10a and the two receiving bodies 20a are alternately arranged along a closed loop-shaped path. Each fixed body 10a is connected to the fixed portions 41 and 42 of the deformed body 40 from the Z-axis positive side, and each receiving body 20a is connected to the receiving portions 43 and 44 of the deformed body 40 on the Z-axis positive side. Is connected from. Each fixed body 10a and each receiving body 20a may be connected to the deformed body 40 from the negative side of the Z axis, or one of the fixed body 10a and each receiving body 20a may be connected from the positive side of the Z axis. The other side may be connected to the deformed body 40 from the negative side of the Z axis.

Further, as shown in FIG. 49, the receiving body 20a has a receiving body surface 23a facing the Z-axis positive direction (upward), and the fixed body 10a is fixed facing the Z-axis positive direction (upward). It has a body surface 13a. In this modification, the distance from the deformed body 40 to the surface of the receiving body 23a and the distance from the deformed body 40 to the surface of the fixed body 13a are both different. More specifically, the fixed body surface 13a is arranged distal to the deformed body 40 from the receiving body surface 20a. In the illustrated example, the upper surfaces of the fixed body 10a and the receiving body 20a (the surface on the positive side of the Z axis) are parallel to the XY plane, and the Z coordinate of the upper surface of the fixed body 10a is the receiving body 20a. It is larger than the Z coordinate of the upper surface of. Such a difference in Z coordinate is set according to the configuration of the attachment object to which the basic structure 1a shown in FIGS. 48 and 49 is attached. Therefore, depending on the configuration of the object to be attached, the Z coordinate of the fixed body surface 13a may be smaller than the Z coordinate of the receiving body surface 23a, or the Z coordinate of the fixed body surface 13a and the Z coordinate of the receiving body surface 23a. The coordinates may be the same.

<Modification example 3>
Further, FIG. 50 is a schematic cross-sectional view showing a further modification example of the basic structure 1 of FIG. In the example shown in FIG. 50, the fixing body 10b is integrally formed with the fixing portions 41 and 42 without interposing the connecting members 33 and 34 (see FIGS. 1 and 3). Even with such a configuration, it is possible to provide the same operation as the basic structure shown in FIG. Although not shown, even if the receiving body 20b is integrally formed with the receiving parts 43 and 44 instead of the fixed body 10b without using the connecting members 31 and 32 (see FIG. 1). good. Alternatively, the fixed body 10b may be integrally formed with the fixed portions 41 and 42, and the receiving body 20b may be integrally formed with the receiving portions 43 and 44.

These modified examples can also be adopted in the deformed bodies 40 shown in FIG. 16 and the deformed body 640 shown in FIG. 18, and the deformed bodies 340 and 440 of the force sensor 301c and 401c shown in FIGS. 28 and 34. is there. Further, the force sensor having such a deformed body can be provided with the same function as each force sensor shown in §1 to §5.

<<< §7. Force sensor according to the fourth embodiment of the present invention >>>
Next, a device for firmly attaching each of the above force sensors to an object to be attached such as a robot will be described.

In each of the above force sensors, a fixed body is connected to, for example, a robot body, and an end effector such as a gripper is connected to the receiving body. As a result, the force or torque acting on the end effector is measured by the force sensor. The connection between the force sensor and the robot body and the end effector is generally realized by fastening screws or bolts to two or four fastening portions provided on the receiving body and the fixed body of the force sensor, respectively. Will be done.

By the way, each of the above force sensors is suitably adopted for measuring a force and / or torque (moment) of a high load. Therefore, the problem of hysteresis is likely to occur, and countermeasures against it are important. In particular, it is important to take measures against hysteresis in the force Fx in the X-axis direction, the force Fy in the Y-axis direction, and the moment Mz around the Z-axis.

In order to avoid hysteresis, it is necessary to increase the fastening force of the fastening portion of the force sensor. For this purpose, it is necessary to increase the diameter of the bolt or increase the number of fastening portions. However, in this case, although the problem of hysteresis is solved or reduced, there is a problem that the outer dimension of the force sensor becomes large. In order to solve such a problem, the force sensor and the robot body and / or the end effector are configured as a combination 1000 as shown in FIG. 41 without increasing the external dimensions of the force sensor. The problem of hysteresis can be solved or reduced.
<7-1. Example 1>
FIG. 41 is a schematic cross-sectional view showing a combination 1000 of a force sensor 101c according to a modification of FIG. 1 and an attachment object 2 to which the force sensor 101c is attached. Further, FIG. 42 is a schematic bottom view showing a sensor-side convex portion 110p of the force sensor 101c shown in FIG. 41 as viewed from the negative direction of the Z axis.

As shown in FIG. 41, the force sensor 101c included in the combination 1000 is attached to the attachment object 2 having the attachment recess 2r. The object to be attached 2 is, for example, the robot body described above. The fixed body 110 of the force sensor 101c has a sensor-side convex portion 110p housed in a mounting recess 2r in a region facing the mounting object 2. Further, the fixed body 110 is formed with a through hole 110a at its outer edge. A plurality of through holes 110a may be provided at equal distances from the Z axis and at equal intervals in the circumferential direction of the fixed body 110. As shown in FIG. 40, a mounting hole 2a is formed in the mounting object 2 at a position corresponding to the through hole 110a. A screw groove is formed on the inner peripheral surface of the mounting hole 2a. The through hole 110a and the mounting hole 2a are formed so that their respective central axes are parallel to the Z axis.

As shown in FIG. 41, the acute angle θ1 formed by the outer peripheral surface 110f of the sensor-side convex portion 110p is relative to the mounting direction (Z direction) when the force sensor 101c is mounted on the mounting object 2. , It is smaller than the acute angle θ2 formed by the inner peripheral surface 2f of the mounting recess 2r. Then, when the sensor-side convex portion 110p is accommodated in the mounting recess 2r of the mounting object 2, the inner peripheral surface 2f of the mounting recess 2r presses the convex portion 110p toward the inside of the mounting recess 2r. .. Further, as shown in FIG. 42, the sensor-side convex portion 110p is provided on the fixed body 110 as a pair of convex portions facing each other at intervals when viewed from the negative direction of the Z axis (lower side in FIG. 41). There is. Since the other configurations of the force sensor 101c are the same as those of the force sensor 1c according to the first embodiment, detailed description thereof will be omitted here.

Such a force sensor 101c is fixed to the attachment object 2 by a bolt 3 as a fixture. That is, the same number of bolts 3 as the through holes 110a are prepared, and these bolts 3 are inserted into the through holes 110a from the side opposite to the side where the mounting object 2 exists. Then, each bolt 3 is screwed into the corresponding mounting hole 2a. In the process of screwing, the convex portion 110p on the sensor side comes into contact with the inner peripheral surface 2f of the mounting recess 2r. From this state, by further tightening each bolt 3, the sensor-side convex portion 110p is formed by the inner peripheral surface 2f of the mounting recess 2r toward the inside of the mounting recess 2r, that is, a pair of sensor-side convex portions 110p. The protrusions are pressed toward the side close to each other. By this pressing, the sensor-side convex portion 110p is elastically deformed (deflected and deformed) toward the inside of the mounting recess 2r. Such elastic deformation of the sensor-side convex portion 110p is smoothly brought about by the relationship between the angle θ2 with respect to the inner peripheral surface 2f of the mounting recess 2r and the angle θ1 with respect to the outer peripheral surface 110f of the sensor-side convex portion 110p.

Then, by further tightening each bolt 3, the sensor-side convex portion 110p is further elastically deformed toward the inside of the inner peripheral surface 2f of the mounting recess 2r, and the gap between the force sensor 101c and the mounting object 2 is created. It gradually decreases, and eventually the gap becomes zero. As a result, the attachment of the force sensor 101c to the attachment object 2 is completed. At this time, the outer peripheral surface 110f of the sensor-side convex portion 110p has substantially the same inclination as the inner peripheral surface 2f of the mounting recess 2r. As a result, due to the restoring force of the sensor-side convex portion 110p, a large force acts between the sensor-side convex portion 110p and the mounting recess 2r.

If the force sensor 101c and the attachment object 2 are configured as the combination 1000 as described above, the force sensor 101c can be firmly fixed to the attachment object 2 without wobbling, and the problem of hysteresis is effective. It can be eliminated or reduced. Of course, it is preferable that the above mounting mode is also adopted at the connecting portion between the receiving body (not shown) and the end effector.

Contrary to the above-mentioned example, the sensor-side concave portion may be provided on the force sensor side, and the mounting convex portion accommodated in the sensor-side concave portion may be provided on the mounting object side. In this case, the structure corresponding to the sensor-side convex portion 110p described above may be adopted for the mounting convex portion, and the structure corresponding to the mounting concave portion 2r described above may be adopted for the sensor-side concave portion. In this case as well, the force sensor can be firmly fixed to the attachment object without wobbling, as in the above-mentioned example.

Further, in the above-described example, the case where the sensor-side convex portions 110p are a pair of convex portions facing each other has been described. However, it is not limited to such an example. For example, the mounting protrusions shown in FIGS. 43 and 44 may also be adopted. 43 and 44 are schematic low-level views showing another example of the mounting convex portion of the force sensor. FIG. 43 shows the protrusions 110Ap continuously provided along the annular path, and FIG. 44 shows the protrusions 110Bp intermittently provided along the annular path. Even in the force sensor in which these protrusions 110Ap and 110Bp are adopted, the force sensor can be firmly fixed to the mounting object 2 without wobbling, as in the above-described example. Of course, when the annular mounting convex portion shown in FIG. 43 or FIG. 44 is adopted, the mounting concave portion formed on the mounting object is also formed in an annular shape.

Further, the mounting convex portion may be formed continuously or intermittently along various closed loop-shaped paths such as a rectangle, a triangle, and a polygon.

<7-2. Example 2>
Next, another example for solving or reducing the problem of hysteresis will be described with reference to FIG. 45.

FIG. 45 is a schematic cross-sectional view showing another combination 1001 by the force sensor 101Ac according to the modified example of FIG. 1 and the attachment object 2A to which the force sensor is attached. As shown in FIG. 45, the force sensor 101Ac constituting the combination body 1001 is directed toward the mounting object 2A at the edge of the through hole 110Aa of the fixed body 110A on the mounting target 2A side (Z-axis negative side). A protruding portion 110Ap is provided. The protruding portion 110Ap may be continuously provided along the edge portion of the through hole 110Aa, or may be provided intermittently along the edge portion. On the outer peripheral surface of the protruding portion 110Ap, a sensor-side tapered surface 110At that tapers toward the mounting object 2A is formed.

Further, in the mounting object 2A constituting the combination body 1001, the edge portion of the mounting hole 2Aa on the force sensor 101Ac side is chamfered, and a mortar-shaped mounting side tapered surface 2At is formed on the edge portion. The acute angle θ3 formed by the sensor-side tapered surface 110At with respect to the mounting direction (Z-axis direction) when the force sensor 101Ac is mounted on the mounting object 2A is the acute angle θ4 formed by the mounting-side tapered surface 2At with respect to the mounting direction. Smaller. The sensor-side tapered surface 110At does not have to be constant over the entire circumference of the edge of the through hole 110Aa, but the acute angle formed with respect to the mounting direction is always such that the corresponding mounting-side tapered surface 2At is in the mounting direction. It is configured to be smaller than the acute angle formed with respect to. Since the other configurations of the combination 1001 are the same as those of the combination 1000 shown in FIG. 41, detailed description thereof will be omitted here. However, in this embodiment, it is not necessary to provide the sensor-side convex portion 110p and the mounting concave portion 2r described above.

Such a force sensor 101Ac is fixed to the attachment object 2A by a bolt 3 as a fixture. That is, the same number of bolts 3 as the through holes 110Aa are prepared, and these bolts 3 are inserted into the through holes 110Aa from the side opposite to the side where the mounting object 2A exists. Then, each bolt 3 is screwed into the corresponding mounting hole 2Aa. In the process of screwing, the sensor-side tapered surface 110At comes into contact with the mounting-side tapered surface 2At. From this state, by further tightening each bolt 3, the protruding portion 110Ap presses the edge portion of the mounting hole 2Aa, that is, the mounting side tapered surface 2At. In other words, the protruding portion 110Ap is pressed toward the inside of the mounting hole 2Aa by the mounting side tapered surface 2At. By this pressing, the protruding portion 110Ap is elastically deformed (deflected and deformed) toward the inside of the mounting hole 2Aa. Such elastic deformation of the protruding portion 110Ap is smoothly brought about by the magnitude relationship between the acute angle θ3 with respect to the sensor-side tapered surface 110At and the acute angle θ4 with respect to the mounting-side tapered surface 2At.

Then, by further tightening each bolt 3, the protrusion 110Ap is further elastically deformed toward the inside of the mounting hole 2Aa, and the gap between the force sensor 101Ac and the mounting object 2A gradually decreases, and eventually the gap Becomes zero. As a result, the attachment of the force sensor 101Ac to the attachment object 2A is completed. At this time, the sensor-side tapered surface 110At of the protruding portion 110Ap has substantially the same inclination as the mounting-side tapered surface 2At. As a result, due to the restoring force of the protruding portion 110Ap, a large force acts between the sensor side tapered surface 110At and the mounting side tapered surface 2At.

If the force sensor 101Ac and the attachment object 2A are configured as the combination 1001 as described above, the force sensor 101Ac can be firmly fixed to the attachment object 2A without wobbling, and the problem of hysteresis is effective. It can be eliminated or reduced. Of course, it is preferable that the above mounting mode is also adopted at the connecting portion between the receiving body (not shown) and the end effector.

<<< §8. Manufacturing method of deformed body >>>
Next, an example of a method for manufacturing a modified body will be described with reference to FIGS. 46 and 47. 46 and 47 are diagrams for explaining a method of manufacturing the modified body 40 shown in FIG. FIG. 46 is a schematic side view showing the second deformed portion 46 before the receiving portion side curved portion 46m and the fixed portion side curved portion 46f are formed, and FIG. 47 is a schematic side view showing the receiving portion side curved portion 46m and the fixed portion side curved portion 46f. It is a schematic side view which shows the 2nd deformation part 46 after the part side bending part 46f is formed.

As shown in FIG. 46, first, a second deformed portion 46 in a state in which the receiving portion side curved portion 46 m and the fixed portion side curved portion 46f are not formed is prepared. The second deformed portion 46 is curved toward the negative side of the Z axis, and a main curved surface 46pa is provided on the surface on the negative side of the Z axis. The connecting portion between the main curved surface 46pa and the fixing portion 42 and the connecting portion between the main curved surface 46pa and the receiving portion 43 both form an acute angle.

Next, as shown in FIG. 47, the connection portion between the second deformed portion 46 and the receiving portion 43 and the connecting portion between the second deformed portion 46 and the fixed portion 42 are in a direction orthogonal to the Z axis (deformed body). The through holes H1 and H2 extend in the radial direction and the depth direction in FIG. 47). In these through holes H1 and H2, when viewed from the radial direction, the arc on the positive side of the Z axis is the main curved surface 46pa of the main curved portion 46p (when the deformed body 540A shown in FIG. 39 is manufactured, the fixed portion side straight line). It is formed so as to be smoothly connected to the portions 545Afs to 548Afs and the receiving portion side straight portion 545Ams to 548Ams). As a result, as shown in FIG. 47, the curved surface on the Z-axis positive side of the through hole H1 formed in the connecting portion between the second deformed portion 46 and the fixed portion 42 constitutes the fixed portion side curved surface 46fa. 2. The curved surface on the Z-axis positive side of the through hole H2 formed at the connecting portion between the deformed portion 46 and the receiving portion 43 constitutes the receiving portion side curved surface 46ma. Therefore, as shown in FIG. 47, the Z-axis positive side portion of the through hole H1 becomes the fixed portion side curved portion 46f, and the Z-axis positive side portion of the through hole H2 becomes the receiving portion side curved portion 46 m.

In the above description, only the method of forming the second deformed portion 46 has been described, but by forming the first, third, and fourth deformed portions 45, 47, and 48 in the same manner, the deformed body 40 Can be easily manufactured. Further, such a manufacturing method can be adopted in the above-mentioned modified body of each force sensor. At this time, the manufacturing method can be appropriately changed according to the shape of each deformed body. For example, in the deformed body having the main curved surface curved inward or radially outward in the radial direction, the curved surface on the fixed portion side, and the curved surface on the receiving portion side described in §6, the above-mentioned through hole H1 and H2 are formed in a direction parallel to the Z axis. Further, a deformed body in which the main curved surface, the fixed portion side curved surface, and the receiving portion side curved surface are provided on the Z-axis positive side, that is, the main curved surface is curved toward the Z-axis positive side, and the fixed portion side is curved. In the deformed body in which the surface and the curved surface on the receiving portion side are curved toward the negative side of the Z axis, the above-mentioned through holes H1 and H2 are through holes formed in the connecting portion between the second deformed portion 46 and the fixed portion 42. The curved surface on the negative side of the Z axis of the hole H1 constitutes the curved surface 46fa on the fixed portion side, and the curved surface on the negative side of the Z axis of the through hole H2 formed at the connecting portion between the second deformed portion 46 and the receiving portion 43. Consists of a curved surface 46 ma on the receiving portion side. Therefore, the Z-axis negative side portion of the through hole H1 becomes the fixed portion side curved portion 46f, and the Z-axis negative side portion of the through hole H2 becomes the receiving portion side curved portion 46 m.

Claims (4)

A force sensor that detects at least one of a force in each axial direction and a moment around each axis in the XYZ three-dimensional coordinate system.
A closed-loop deformed body that elastically deforms due to the action of force or moment,
A detection circuit that outputs an electric signal indicating an acting force or moment based on the elastic deformation generated in the deformed body is provided.
The deformed body is positioned adjacent to at least two fixed parts fixed to the XYZ three-dimensional coordinate system and the fixed parts in a closed loop path of the deformed body, and is affected by a force or a moment. It has at least two receiving portions and a deformed portion located between the fixed portion and the receiving portion that are adjacent to each other in the closed loop path.
The deformed part is
A main curved portion having a main curved surface curved in the Z-axis direction,
A fixed portion-side curved portion that connects the main curved portion and the corresponding fixed portion and has a fixed portion-side curved surface that is curved in the Z-axis direction.
The main curved portion and the corresponding receiving portion are connected to each other, and the receiving portion side curved portion having a curved surface on the receiving portion side curved in the Z-axis direction is provided.
The main curved surface, the curved surface on the fixed portion side, and the curved surface on the receiving portion side are both provided on the Z-axis positive side or the Z-axis negative side of the deformed portion, and the directions of curvature are different from each other. ,
The detection circuit is a force sensor that outputs the electric signal based on the elastic deformation generated in the main curved portion. The main curved surface, the fixed portion side curved surface, and the receiving portion side curved surface are both provided on the Z-axis negative side of the deformed portion.
The main curved surface is curved toward the negative side of the Z axis.
The force sensor according to claim 1, wherein the curved surface on the fixed portion side and the curved surface on the receiving portion side are curved toward the positive side of the Z axis. A force sensor that detects at least one of a force in each axial direction and a moment around each axis in the XYZ three-dimensional coordinate system.
A fixed body fixed to the XYZ three-dimensional coordinate system,
A closed-loop deformed body that surrounds the Z-axis, is connected to the fixed body, and causes elastic deformation by the action of a force or moment.
A receiving body that is connected to the deformed body and moves relative to the fixed body by the action of a force or moment.
A detection circuit that outputs an electric signal indicating a force or moment acting on the receiving body based on the elastic deformation generated in the deformed body is provided.
The deformed body has at least two fixed portions connected to the fixed body and at least two receiving portions connected to the receiving body and positioned adjacent to the fixed portion in the circumferential direction of the deformed body. And a deformed portion positioned between the adjacent fixed portion and the receiving portion.
The deformed part is
A main curved portion having a main curved surface curved in the Z-axis direction,
A fixed portion-side curved portion that connects the main curved portion and the corresponding fixed portion and has a fixed portion-side curved surface that is curved in the Z-axis direction.
The main curved portion and the corresponding receiving portion are connected to each other, and the receiving portion side curved portion having a curved surface on the receiving portion side curved in the Z-axis direction is provided.
The main curved surface, the curved surface on the fixed portion side, and the curved surface on the receiving portion side are both provided on the Z-axis positive side or the Z-axis negative side of the deformed portion, and the directions of curvature are different from each other. ,
The detection circuit outputs the electric signal based on the elastic deformation generated in the main bending portion.
The receiving body has a receiving body surface facing the Z-axis positive direction or the Z-axis negative direction.
The fixed body has a fixed body surface facing the Z-axis positive direction or the Z-axis negative direction.
A force sensor in which the distance from the deformed body to the surface of the receiving body and the distance from the deformed body to the surface of the fixed body are different. A force sensor that detects at least one of a force in each axial direction and a moment around each axis in the XYZ three-dimensional coordinate system.
A closed-loop deformed body that elastically deforms due to the action of force or moment,
A detection circuit that outputs an electric signal indicating an acting force or moment based on the elastic deformation generated in the deformed body is provided.
The deformed body is positioned adjacent to each fixed part in a closed loop-shaped path of the deformed body and four fixed parts fixed to the XYZ three-dimensional coordinate system, and is subjected to the action of a force or a moment. It has one receiving portion and a deformed portion positioned between each fixed portion and each receiving portion adjacent to each other in the closed loop path.
The deformed part is
A main curved portion having a main curved surface curved in the Z-axis direction,
A fixed portion-side curved portion that connects the main curved portion and the corresponding fixed portion and has a fixed portion-side curved surface that is curved in the Z-axis direction.
The main curved portion and the corresponding receiving portion are connected to each other, and the receiving portion side curved portion having a curved surface on the receiving portion side curved in the Z-axis direction is provided.
The main curved surface, the curved surface on the fixed portion side, and the curved surface on the receiving portion side are both provided on the Z-axis positive side or the Z-axis negative side of each deformed portion, and the directions of curvature are different from each other. ,
The detection circuit is a force sensor that outputs the electric signal based on the elastic deformation generated in the main curved portion.

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